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Accident Prevention Manual

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Accident Prevention Manual for Business & Industry: Engineering & Technology 13th edition National Safety Council Compiled by Dr. S.D. Allen Iske, Associate Professor – PowerPoint PPT presentation

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Title: Accident Prevention Manual


1
  • Accident Prevention Manual
  • for Business Industry
  • Engineering Technology
  • 13th edition
  • National Safety Council

Compiled by Dr. S.D. Allen Iske, Associate
Professor University of Central Missouri
2
CHAPTER 25
  • HOT WORKING OF METALS

3
Hazardous Materials
  • Dusts, solvents, and other materials present a
    health hazard in foundries.
  • Dust is generated in many foundry processes and
    presents a twofold problem
  • Cleaning to remove deposits
  • Control at the point of origin to prevent further
    dispersion and accumulation
  • Vacuum cleaning is the best way to remove dust in
    foundries.
  • Once dust has been removed, prevent further
    accumulation by using local exhaust systems (LEV)
    that remove it at the point of origin.

4
Hazardous Materials (Cont.)
  • Solvents evaluate each solvent on the basis of
    its chemical ingredients
  • Proper labeling, substituting less hazardous for
    more hazardous chemicals, limiting the quantities
    in use, and using other methods of control can
    help minimize the toxic and flammable hazards
    involved in using solvents.
  • Other materials many metal resins, and other
    substances present safety and health hazards

5
Hazardous Materials (Cont.)
  • Other hazardous materials that are found in
    various stages and locations of hot metal
    operations include
  • acrolein
  • beryllium
  • carbon as sea coal
  • carbon monoxide (CO)
  • chromium
  • fluorides
  • lead
  • magnesium dust or chips
  • manganese
  • phosphorus
  • resins and resin dusts
  • silica
  • sulfur dioxide

6
Hazardous Materials (Cont.)
  • Iron-oxide fumes and dusts are created during
    melting, burning, pouring, grinding, welding, and
    machining of ferrous castings
  • Use LEV to vent these fumes.

7
Medical Program
  • Baseline physical examinations, including chest
    x-rays, audiometric tests, and pulmonary function
    tests
  • Periodic physical examinations to detect
    incipient disease and to help reclassify workers
    as needed
  • Adequate first aid facilities and employee
    training in first aid
  • Observe regulatory requirements if respirators
    must be worn
  • Industrial hygiene monitoring where needed

8
Medical Program (Cont.)
  • Industrial hygiene equipment, such as a hand-held
    meter that detects minerals in solution, are
    extremely helpful in identifying metal
    contaminants of industrial effluents and water
    quality.
  • It can measure a wide concentration range,
    meeting various international and regulatory
    standards.

9
Medical Program (Cont.)
  • Ensure employees are aware of specific hazards to
    which they may be exposed and the proper control
    or emergency responses to those hazards.
  • Make Safety Data Sheets (SDSs) available to all
    employees.

10
Personnel Facilities
  • Encourage frequent washing with soap and water,
    and install adequate facilities.
  • Coreroom workers whose hands and arms may be
    exposed to sand and core oil mixtures are
    candidates for dermatitis.
  • Prolonged contact with oil, grease, acids,
    alkalis, and dirt can produce dermatitis.
  • Reference industrial sanitation standards.
  • Sanitary food preparation and service is
    especially important in nonferrous foundries.
  • Prohibit eating in work areas.

11
Work Environment in Foundries
  • Good housekeeping, ventilation, and light help
    maintain a safe and healthy work environment.
  • Proper inspections, maintenance, and fire
    protection increase workers safety in foundries.
  • Housekeeping
  • Clean machines and equipment after each shift,
    and keep them reasonably clean during the shift.
  • Place all trash in the proper trash bins.
  • Keep the floors and aisles in the work area
    unobstructed.
  • Properly stack and store materials.

12
Work Environment in Foundries (Cont.)
  • Floor loading
  • Many buildings are used for purposes for which
    they were not designed.
  • Deadweight of platforms and lift trucks introduce
    floor load problems.
  • Overhead cranes and hoists from wood ceiling
    joists severely taxes roof and floor members.
  • Insurance engineers or local building inspectors
    can help determine safe floor load limits.

13
Work Environment in Foundries (Cont.)
  • Ventilation
  • Control of air contaminants is the primary
    purpose of ventilation in foundries.
  • The need for ventilation may be determined by one
    of more of the following
  • Federal, state, and local regulations or
    standards
  • Comparison with similar operations in a like
    environment
  • Collection and analysis of representative air
    samples taken by qualified personnel in the
    breathing zone of workers

14
Work Environment in Foundries (Cont.)
  • Noise control
  • Controlling excessive levels of noise, more than
    85dBA, may sometimes be difficult.
  • Engineering is not always possible because of a
    lack of technology or is impractical.
  • Develop a hearing conservation program that
    provides approved hearing protection for each
    worker.
  • Minimize exposure to identified high-noise-level
    hazards.

15
Work Environment in Foundries (Cont.)
  • Lighting
  • Good lighting is difficult to achieve.
  • Where craneways are used, light fixtures must be
    placed high and at considerable distances from
    work areas.
  • Nevertheless provide good lighting for each work
    area.

16
Work Environment in Foundries (Cont.)
  • Inspection and maintenance
  • Follow standard inspection and maintenance
    procedures in foundries.
  • Carefully select maintenance personnel.
  • Train them in safe practices, especially in
    procedures for locking out controls and isolating
    other energy sources.

17
Work Environment in Foundries (Cont.)
  • Fire protection
  • Make periodic fire inspections.
  • Perform emergency fire fighting drills.
  • If a fire brigade is present, it will aid the
    safety program by keeping its members, as well as
    other employees in the foundry, safety conscious.

18
Work Environment in Foundries (Cont.)
  • Facility structures
  • Entrances and exitsall doors should have an
    eye-level window opening.
  • Stairways provide handrails, standard
    guardrails, and toeboards for stairs having four
    or more risers.
  • Floors and pits install special types of
    flooring where explosion hazards exists keep
    clean and dry.
  • Galleries provide galleries with solid,
    leak-proof floors.
  • Gangways and aisles should be firm enough to
    withstand daily traffic.

19
Work Environment in Foundries (Cont.)
  • Compressed air hoses
  • Do not use air hoses to clean clothes.
  • Improper use and horseplay have caused severe
    injuries to internal organs and eardrums.
  • Reduce air to less than 30 psig.
  • Install whip checks at all joints.
  • Prohibit blowing and brushing sand from new
    castings without regard for dust clouds produced.
  • Substitute vacuum methods when possible.
  • Train workers on the safe use of air hoses.

20
Materials Handling in Foundries
  • General safe working recommendations
  • Instruct workers in the safe methods of manual
    and mechanical materials handling.
  • Provide PPE such as eye protection, safety hats,
    face shields, and gloves.
  • Plan the sequence and method of handling
    materials to eliminate unnecessary handling.
  • Safeguard mechanical devices and set up
    inspection procedures to ensure proper
    maintenance.
  • Keep good order at storage piles and bins, and
    pile materials properly.
  • Keep ground and floor surfaces level.
  • Install side stakes or sideboards on tramway or
    railroad cars to prevent materials from falling
    off.
  • Chock railroad cars and flag tracks.

21
Materials Handling in Foundries (Cont.)
  • Sand, coal, and coke
  • Prevent falls through hoppers while unloading
    bottom-dump railroad cars with fall protection.
  • Be sure observers are on the scene and prepared
    to summon help in emergencies.
  • Use safety ratchet wrenches for hopper doors to
    keep the doors from swinging and striking
    workers.
  • Prevent hand and foot injuries by using safety
    car movers instead of ordinary pinch bars to spot
    cars by hand.
  • To reduce cave-ins of loose material, prohibit
    the undermining of piles and avoid overhangs.
  • Prevent electric shock by grounding portable
    belt-conveyor loaders.
  • To keep dump cars under repair from being moved,
    use locking switches and car chocks.

22
Materials Handling in Foundries (Cont.)
  • Ladles
  • Provide a manually operated safety lock and
    suitable covers for portable ladles.
  • Thoroughly dry out and heat ladles before use.
  • Provide LEV to control vapors and fumes.
  • Ensure that the ladle is suited for its intended
    operation and make necessary adjustments.

23
Materials Handling in Foundries (Cont.)
  • Hoists and cranes
  • Require preventive maintenance program.
  • Gear the program to ensure that the operation is
    much safer than simply to comply with minimal
    regulations.
  • Conduct inspections on a weekly basis by trained
    specialists.
  • Nondestructive testing (ultrasonic) may be
    required to locate cracks and other issues.

24
Materials Handling in Foundries (Cont.)
  • Conveyors
  • Conveyors are used to carry sand to and from the
    mixing room.
  • An endless conveyor is used to handle molds.
  • When installing a system, guard shear points,
    crush points, and moving parts.
  • Where conveyor systems run over passageways and
    working areas, protect employees beneath them
    with screens, grating, or guards.
  • Guarding should be strong enough to resist the
    impact of the heaviest piece handled.

25
Materials Handling in Foundries (Cont.)
  • Storage
  • Store materials and equipment not in regular use
    in a safe, orderly manner on level and firm
    foundations.
  • When removing equipment and materials from floor
    level or from storage piles, do not undermine
    piles and cause cave-ins.
  • Cover bottom feeding hopper bins.
  • Use racks and shelves to store patterns and
    provide keepers.
  • Store flammable liquids in accordance with NFPA
    30.
  • Ensure good lighting and floor conditions in
    storage areas.

26
Materials Handling in Foundries (Cont.)
  • Slag disposal
  • Design furnaces and pits with removable
    receptacles into which slag and kish (separated
    graphite) may flow or be dumped.
  • Unless disposed of in the molten state, provide
    enough receptacles so slag can solidify before
    dumping.
  • Use slag or cinder pots to decrease slag pit
    accumulation.
  • The pots can be set aside for cooling and
    eliminate explosion dangers.
  • Dump where there is absolutely no water or
    dampness.
  • Water might cause an explosion if some slag is
    still molten.
  • Before breaking up slag allow it to stand for
    several hours.

27
Cupolas
  • Definition Vertical cylindrical furnaces used to
    melt iron
  • Charging
  • Dangers are principally confined to handling
    material.
  • Never unevenly load or overload barrows or
    buggies.
  • Break open scrap cylinders, tanks, and drums
    before charging to prevent an explosion.
  • Install railings or other safeguards underneath
    the elevators, machines, hoists, and cranes.

28
Cupolas (Cont.)
  • Charging floor
  • Use bolted, heavy steal plates.
  • Install brick flooring near the furnace to avoid
    extremely hot steel flooring.
  • Observe good housekeeping.
  • Construct railings from angle iron at 42 in.
    high, and 4-in. toeboards around all floor
    openings.
  • Place guardrails across the charging opening.

29
Cupolas (Cont.)
  • Carbon monoxide (CO)
  • Is generated during some cycles in the operation.
  • CO is an explosion hazard if it gets into the
    wind boxes and blast pipes.
  • Supply adequate ventilation in the back of the
    cupola, and open two or more tuyeres after the
    blowers are shut down.
  • Locate CO indicators around the cupola that light
    and give a loud sound.
  • If CO concentration is continually above 200 ppm,
    an engineering assessment should be considered.
  • OSHA 8-hour TWA is 35 ppm and the ceiling limit
    is 200ppm.

30
Cupolas (Cont.)
  • Blast gates
  • Blast Gates and explosion doors are successfully
    used to prevent damage from gas explosions.
  • Often placed in front of tuyeres so fresh air can
    enter when the blowers are down.
  • Never close them until the blast has entered the
    wind box and driven out all gas.
  • Equip positive-pressure blowers with safety
    valves.
  • Every cupola should have at least one safety
    tuyere, with a small channel.

31
Cupolas (Cont.)
  • Tapping out
  • Operators should not thrust the bott directly
    into the stream of metal.
  • Dropping the cupolas bottom doors
  • Place temporary supports under the bottom doors.
  • One of the best methods for doing this is to use
    a block and tackle with a wire rope and chain
    leader attached to the props that support the
    doors.
  • Carefully inspect beneath the cupola for water.
  • Have one worker check the danger zone and warn
    nearby employees with a horn or other signal.

32
Cupola (Cont.)
  • Suggested method of raising the bottom doors of
    the cupola by mechanical means.
  • Only careful and experienced workers should
    repair a cupolas lining.
  • A screen placed over the charging door prevents
    falling objects from dropping on workers
    repairing cupola linings.

33
Crucibles
  • The principal danger in handling refractory clay
    crucibles is that one may break when full of
    molten metal.
  • Have a trained inspector check all new crucibles
    for cracks, thin spots, and other flaws.
  • Return to the manufacturer those showing signs of
    dampness.
  • Examine the packages and the car in which they
    were shipped to find out whether or not they were
    exposed to moisture in transit.

34
Crucibles (Cont.)
  • Storing
  • Store in a warm dry place. Generally best in an
    oven on top of a core oven, or some other point
    where waste heat can be used
  • Annealing process
  • Crucibles are heated over 810 hours before use.
  • Do not allow crucibles to cool before they have a
    charge.
  • Moisture in walls of crucibles is quickly
    converted into steam and could become a crack or
    pinhole.

35
Crucibles (Cont.)
  • Charging
  • Proper care of crucibles is good economy as well
    as good safety.
  • To protect the crucibles lining and structure,
    establish a process for cleaning.
  • Charge them carefully, do not throw in ingots
    with such force that they bend the bottom walls
    of the crucible out of shape.
  • At white heat, they are soft and easily forced
    out of shape handle with great care.

36
Crucibles (Cont.)
  • Handling
  • Select tongs of the proper size and shape.
  • Never drive tong rings down tight with a skimmer.
  • Avoid ramming the fuel bed around a crucible.
  • Where possible, use a mechanical device to remove
    heavy crucibles, those exceeding 100 lbs.
  • Observe safe operating practices of hoists when
    using air or electric hoists to move large
    crucibles.

37
Ovens
  • Principal hazards in the construction and
    operation of core ovens and mold-drying ovens are
    excessive smoke, gas, and fumes.
  • Other unsafe conditions are unprotected firing
    pits unguarded vertical sling doors or their
    counterweights, which may drop on workers and
    flashbacks from fireboxes.
  • Guard firing pits.
  • Install safe vertical sliding doors, wire ropes
    and chains, sturdy fastenings.
  • Thoroughly inspect all sliding doors at frequent
    intervals.

38
Oven Ventilation
  • Where fumes, gases, and smoke are emitted from
    drying ovens, install ducts and exhaust fans near
    the ovens doors hoods and Install the proper
    size flues to prevent flashbacks.
  • Equip core ovens with explosion vents.
  • Lightweight panels may be installed on top of the
    oven, or the oven may have hinged doors with
    explosion latches.
  • Larger ovens should have forced-draft
    ventilation.
  • Interlock the ventilation system with the gas
    supply through a time relay that allows for three
    changes of air in the oven before burners are lit.

39
Oven Inspection
  • Before core ovens are lit, they must be
    thoroughly inspected.
  • Only trained and qualified personnel should do
    this work.
  • Establish an inspection and preventive
    maintenance program for core ovens.
  • The first step of an inspection should always be
    to shut off the main valve that controls the fuel
    supply and check the pilot lights before entering
    to make sure they are off.

40
Foundry Production Equipment
  • On production-line equipment, fully guard moving
    parts and other common machine hazards in
    accordance with standard practices.
  • Ground electrical equipment to eliminate shock
    hazards.
  • Allow repairs only on equipment that is locked in
    the OFF position and after all other sources of
    energy have been eliminated.
  • Observe LOTO procedures for operations that
    require an employee to enter for cleaning or
    repairs.

41
Foundry Production Equipment (Cont.)
  • Sand mills and dough mixers
  • Principal danger exists when operators reach in
    for samples of sand or attempt to shovel out sand
    while the mill is running.
  • In doing so, they may be caught and pulled into
    the mill.
  • Guard them so that entry into either device is
    limited.
  • Train employees in safe operation of both
    machines.

42
Foundry Production Equipment (Cont.)
  • Sand cutters
  • Throw sand and pieces of metal with bullet-like
    force.
  • Guard so that efficiency of the operation is not
    reduced or give operators proper PPE if guarding
    is not feasible.
  • Sifters
  • Guard with enclosures or angle iron pipe
    railings.
  • Place controls within reach of operators.
  • Anchor portable sifters.

43
Foundry Production Equipment (Cont.)
  • Molds and cores
  • The principal hazards in hand molding and core
    making include letting flasks down on feet,
    pinching fingers between flasks, dropping heavy
    core boxes on feet, cutting hands on nails and
    other sharp pieces of metal in the sand, and
    stepping on nails.
  • Minimize hand and foot injuries by training
    workers to handle flasks and core boxes properly
    and to wear foot protection with stout soles.
  • Screening or magnetic separation to remove nails
    and other sharp metal from the sand is also
    essential.

44
Foundry Production Equipment (Cont.)
  • Molds and cores
  • In general molding and core making, gagger rods
    and core wires are cut, straightened, and bent
    using hammers and cutting sets, which can create
    flying pieces of metal and dirt.
  • Brace heavy cores in large molds to keep the core
    from toppling over.
  • Prohibit work underneath molds suspended from
    cranes.
  • Vent molds properly to avoid explosions during
    pouring.

45
Foundry Production Equipment (Cont.)
  • Molding machines
  • Three types of molding machines are used in
    foundries straight, semi-auto, and auto.
  • Equip all molding machines with two-hand controls
    for each operator.
  • On automatic molding machines, install shields or
    apron-type metal guards.
  • The carry-out person should stand clear of the
    squeeze at the back of the machine.
  • Operators should never touch the frame while it
    is moving.

46
Foundry Production Equipment (Cont.)
  • Core-blowing machines
  • Straight, semiautomatic, and automatic
    core-blowing machines are used in foundries
  • On semi-auto and auto machines, guard core-box
    push cylinders, counterweight cable pulleys,
    wheel guide, and table-adjusting footpads.
  • Install an automatic barrier guard between the
    operator and machine.
  • Equip auto and semi-auto machines with
    double-solenoid valves, and maintain the slide
    valve well.

47
Core-Blowing Machines
  • To prevent sand blows, maintain parting lines in
    good condition.
  • Figure 257 of a core box shows a rubber dike
    seal, which prevents sand blows and abrasion of
    the box.

48
Flasks
  • Iron or steel are preferable to wood.
  • Discard defective flasks immediately.
  • Have competent inspectors inspect flasks at
    frequent intervals.
  • Flask trunnions should have end flanges at least
    twice the diameter of the trunnions to minimize
    the danger of hooks slipping or jumping.
  • Large flasks should have loop handles.
  • Design trunnions and handles with a safety factor
    of at least 10.

49
Foundry Production Equipment
  • Sandblast rooms Should be dust-tight and workers
    should wear air supplied respirators when working
    in them.
  • Tumbling barrels Need frequent care to be kept
    dust-tight.
  • Shake-out machines Present the danger of hands
    and feet being crushed or arms and legs being
    broken. Steel-toed boots are recommended.

50
Cleaning and Finishing Foundry Products
  • Have qualified personnel mount and change
    abrasive grinding wheels.
  • Keep required wheel guarding intact.
  • Speed-test new wheels before allowing them to be
    used on the job.
  • Require operators to wear full PPE for eyes,
    face, hands, and feet.
  • Dust generated by abrasive wheels is a potential
    health hazard.
  • Keep the space around the machines dry, clean,
    and as free as possible of castings and other
    obstructions.

51
Magnesium Grinding
  • Dust-collection systems should eliminate the
    possibilities of fire and explosion.
  • The dust should be wet down by a heavy spray of
    water and immediately washed into a sludge pit,
    where the dust is collected under water to reduce
    the fire hazard.
  • Keep sludge pits well ventilated.
  • Do not let wet magnesium dust stand and become
    partially dried.
  • The collection system must have no filters or
    obstructions that allow the dust to accumulated.
  • Minimize bending and turning of pipes, and clean
    them often.

52
Magnesium Grinding Dust Collection System
53
Magnesium Grinding
  • General housekeeping
  • Essential for the safe handling of magnesium
  • Prevents accumulations of magnesium dusts on
    benches, floors, window ledges, overhead beams
    and pipes, and other equipment
  • Do not use vacuums to collect the dusts, have it
    swept up and placed in a covered, plainly
    labeled, iron containers.
  • Do not mix magnesium dust with regular floor
    sweepings.
  • If it is not recycled back into the process,
    dispose of dust according to local, state, and
    federal regulations.

54
Magnesium Grinding (Cont.)
  • Injury and fire prevention
  • Start and run the grinder and exhaust system for
    a few minutes before beginning the grinding
    operation.
  • Have operators of grinding equipment wear leather
    or smooth, fire-retardant clothing, not
    coarse-textured or fuzzy clothing. Brush clothing
    frequently.
  • Have operators wear goggles or a full-brim helmet
    with a face shield, and gloves.
  • Keep machine tools sharp and properly grounded
    for magnesium, or friction sparks may cause
    fires.
  • Use neutral mineral oils and greases for cooling
    and lubrication. Animal or vegetable oils,
    acid-containing mineral oils, or oil-water
    emulsions are potentially hazardous.

55
Cleaning and Finishing Foundry Products
  • Chipping
  • Where castings are cleaned or chipped, provide
    tables, benches, and jigs specifically designed
    and shaped to hold the particular casting
  • Install screens or partitions to protect other
    employees from flying chips.
  • Install hoods and exhaust system in these areas
    to remove dust.
  • Require workers to wear eye and face protection
    when cleaning or chipping castings.

56
Cleaning and Finishing Foundry Products (Cont.)
  • Welding
  • Considerable welding is done when cleaning or
    reclaiming castings.
  • To prevent fires in welding areas, spread sand on
    the floor as it is a noncombustible and plentiful
    material, but it is also a health hazard.
  • Powder washing is a method of cleaning castings
    in which a stream of powdered iron oxide is
    introduced into a gas flame to intensify the heat
    produced.
  • When powder washing is used to clean or cut
    sprues, gates, and risers from alloyed castings,
    use exhaust ventilation.

57
Cleaning and Finishing Foundry Products (Cont.)
  • Power presses
  • Used widely in finishing departments of foundries
  • Provide sufficient aisle space, good
    housekeeping, and effective lighting.
  • Properly guard and maintain machines in good
    working order.
  • Carefully select and train operators.
  • Use mechanical feed and ejection equipment
    whenever possible.

58
Forging Hammers
  • There are several types of forging hammers
  • open-frame
  • gravity-drop
  • steam hammer
  • air hammer
  • Each require special safeguarding and work
    practices despite having similar hazards.

59
Open-Frame Hammers
  • Constructed so the anvils assembly is separate
    from the foundation of the frame and operating
    mechanism of the hammer.
  • They may be single or double frames.
  • Generally use flat dies, and the work done allows
    for more machining of material.
  • Open-frame hammers are used when
  • the quantity of forgings to be run is too small
    to warrant the expense of impression dies.
  • the forgings are too large or too irregular to be
    contained in the usual impression dies.

60
Gravity-Drop Hammers
  • Drop forgings in closed-impression dies are
    produced on these hammers.
  • The impact of the free falling hammers blow
    shapes the forging through one or more states to
    the finished shape.
  • Forgings on gravity-drop hammers may range in
    weight from less than 1 oz to 100 lb and be made
    of any type of malleable metal.

61
Steam Hammers and Air Hammers
  • Also classified as drop hammers.
  • Steam or air pressure goes through a piston and
    cylinder to raise the ram and die to assist in
    striking the impact blow.
  • They strike a heavier blow than a gravity-drop
    hammer using an equivalent falling weight.
  • The falling weight of the ram assembly and upper
    die of double-acting steam hammers ranges from
    1,000 to approximately 50,00 lb.
  • These hammers are made with many built-in safety
    features.

62
Hazards of Forging Hammers
  • For the most part, all types of hammers have
    identical hazards.
  • Frequent causes of injury include
  • being struck by flying drift and key fragments or
    by flash or slugs
  • using feeler gauges to check the guides, wear, or
    the matching of dies
  • using material-handling equipment improperly,
    such as tong lifts
  • having fingers, hands, or arms crushed between
    dies
  • having fingers crushed between tong reins
  • receiving kickbacks from tongs
  • using swabs or scale-blowing pipes with short
    handles
  • being burned by hot scale
  • dropping stock on the feet
  • noise-induced hearing loss
  • foreign objects in the eye

63
Guarding
  • Maintenance personnel are exposed to the
    potential danger of crushing injuries when they
    remove and install parts on the opt of the hammer
    and when they remove sow blocks, anvils, and
    columns.
  • To avoid these injuries, provide and use means
    for locking out power.
  • Provide safe footing for personnel by installing
    catwalks and guardrails on hammers.

64
Gravity-Drop Hammer Guarding
  • Use a hand lever rather than a treadle for cold
    restrike operations.
  • Provide two-hand tripping controls if
  • the material being forged is not held by the
    hands or by hand tools
  • a safety stop or tripping lever cannot be
    installed.
  • On board-drop hammers, provide a substantial
    guard around the boards above the rolls.
  • This prevents the boards form falling should they
    break or come loose.

65
Gravity-Drop Hammer Guarding (Cont.)
  1. Sheet steel board guard box
  2. Screen platform made from No. 9 metal
  3. Steel ram safety stop that swivels on the left
    column
  4. Safety chain to restrain tie bold and nut
  5. Catwalk and belt catcher

66
Steam and Air Hammer Guarding
  • Should have a stop valve or quick-opening and
    quick-closing valve.
  • Provide a safety head in the form of a steam or
    air cushion to prevent the piston from striking
    the top of its cylinder.
  • Connect the cylinder heads and safety heads
    bolts to an anchored wire rope.
  • If the hammer has no self-draining arrangement,
    install a drain cock.
  • If air or steam is used to remove scale, provide
    a quick shutoff valve so that the pressure can be
    regulated.

67
Key-Driving Rams
  • A pneumatic key-driving ram is superior to a
    manually operated one and offers a far greater
    margin of safety.

68
Scale Guards
  • Scale guards confine pieces of flying scale,
    install them as standard equipment on the back of
    every hammer.

69
Guarding
  • Treadles and pedals
  • Provide treadles and pedals with ample clearance.
  • Guard them to prevent them from being
    unintentionally tripped by a falling object.
  • Guard any portion at the rear of the hammer so
    scrap material cannot interfere.
  • Use interlocks on treadles.

70
Guarding (Cont.)
  • Flywheels and pulleys
  • Enclose with a guard that is strong enough to
    prevent the pulley from falling to the floor
    should the shaft break.
  • In some instances, the guard enclosure is
    supported from the floor by an I-beam.
  • Restrain all cylinder bolts, gland bolts, and
    guide bolts and liners, as well as the head
    assembly over the operators working position.

71
Guarding (Cont.)
  • Safety ropes keep the cylinder head, tie plate
    bolts, and gland bolts from falling if they
    break.
  • The tie plate bolts and gland bolts are secured
    to the master rope.
  • The gland bolt safety rope should be tight enough
    to prevent a broken gland bolt from swinging down
    and striking the ram.

72
Safety Props
  • Provide safety props equipped with handles at the
    middle.
  • Require workers to use them when repairing,
    adjusting, or changing dies.
  • The props should be held in place while power is
    released this permits the weight of the upper
    die and the ram to rest on the props.
  • Operators should never place their hands on top
    of a prop.
  • Ram props should be made of steel, magnesium, or
    aluminum.

73
Die Keys
  • Never use mushroomed keys keys should be tapered
    for clearance.
  • Keys must be the correct length.
  • If keys project farther, they become a hazard to
    the operator working in front.
  • They may also break off while the hammer is
    operating and fall between the dies in back.
  • Stock an adequate supply of die keys so drifts
    will be needed only when the end of a key becomes
    distorted and must be cut off before the key can
    be driven out.

74
Design of Dies
  • Usually made of chrome, nickel, of molybdenum
    stellite due to high heat, shock, and abrasion
    resistance.
  • Selection of the proper die steel in the correct
    range of hardness is important in controlling
    checking and breakage.
  • Size, amount of striking surface, and height are
    other factors in the safe design of dies.
  • The dies must be made so they meet in precise
    alignment.
  • Frequent inspection is necessary.
  • Avoid welding to correct defects or to maintain
    specifications.

75
Setup and Removal of Dies
  • When forge dies are set up or removed, the hammer
    operator should act as leader of the group.
  • The operator should see that all efforts are
    coordinated and that all safety rules are
    observed.
  • Pre-setup activities
  • Clean around the hammer.
  • Do not perform maintenance work on the equipment
    when setting up a die.
  • Ensure good lighting and flooring.

76
Setup and Removal of Dies (Cont.)
  • Setup
  • Prop the ram securely and shut off and lockout
    the power.
  • Drive die dowels into the dowel holes in the die
    shank.
  • After the bottom die of a steam hammer has been
    set in place, drive the bottom key to help line
    up the die and partially tighten it.
  • Invert the top die and set it in position so the
    dies are face to face with the match lines
    aligned. (Reverse this procedure for a
    gravity-drop hammer set and key the top die
    first.)
  • Remove the safety prop between the ram and sow
    block.
  • Let the ram descend slowly until it engages the
    die.

77
Setup and Removal of Dies (Cont.)
  • Removing dies
  • Clear the area around the hammer.
  • Shutoff and lock out the hammers energy sources.
  • Use a special type of adjustable knockout that is
    held in position mechanically rather than
    manually.
  • After die keys have been driven out, raise the
    ram and prop it at once.
  • After removing the dies from the hammer, extract
    the dowels.
  • Load the removed dies onto low, steel pallets and
    take them from the area as soon as possible.

78
Setup and Removal of Dies (Cont.)
  • Adjustable knockout key

79
Forging Upsetters
  • This is a horizontal machine that forges hot bar
    stock, usually round, into many forms via
    squeezing action.
  • Enclose the machine as much as possible, except
    for the feed area.
  • For safe operating conditions, keep the area
    around the machine clean and clear of
    obstructions and litter.
  • Use lockout procedures before attempting to make
    any changes to dies, heading tools, stock gauges,
    or backstops.

80
Nondestructive Testing
  • Visual observation cannot locate all small,
    below-the-surface defects in casts and forged
    metals without damaging the parts being tested.
  • Proper nondestructive testing reveals defects
    inherent in metals and other solid materials or
    those that result from processing or in-service
    use.

81
Nondestructive Testing (Cont.)
  • The types of testing most commonly used for
    forged and cast metals are the following
  • magnetic particle inspection
  • penetrant inspection
  • ultrasonic methods
  • triboelectric method
  • electromagnetic tests
  • radiography
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