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Teikoku Seibyo's Technological Capabilities

We respond to the needs of our customers

Teikoku Seibyo maintains both hot and cold forging facilities.
Capitalizing on the advantages of each forging technique, orders are accepted for not only regular specification products but also for unusual bolts or special application steel bolts in lots of any size.
Teikoku Seibyo is also fully equipped to function as a single source supplier of bolt post production processing and respond to a variety of customer fastener requirements.

JIS Certified Product Categories

October 1951 JIS E1108 Track spikes
December 1952 JIS E1109 Rail Screw spikes
December 1953 JIS B1107 Fishplate and rail joint bolts / nuts
August 1963 JIS B1180 Hex bolts (strength classification 4.6 – 6.8)
November 1973 JIS B1186 High tension hex bolt sets for friction points
April 1989 JIS B1198 Headed studs
November 2000 JIS B1180 Hex bolts (strength classification 4.6 – 12.9)

Forging - Basic Information

Plasticity Processing
An object will deform under force, and will not return to its original form if this force exceeds a certain magnitude, even if the force is removed.
This kind of deformation is called “plastic deformation.” The manufacturing process that uses this plastic deformation to form objects is called “plasticity processing.”

The manufacturing method of “plasticity processing” in the case of metal materials (excluding sheet metals) is called “forging.”

Cold Forging / Hot Forging
Generally speaking, forge work at temperatures between 600 – 900 degrees Celsius is called “warm forging,” at temperatures above 900 degrees is called “hot forging,” and forge work at room temperature is called “cold forging.”
Cold forging enables greater manufacturing precision than hot forging.
However, the higher hardness of the work piece during cold forging requires a comparatively greater amount of forming pressure for the size of the work piece. For this reason, cold forging is more suited to relatively smaller work pieces.
Also, due to the low difference in hardness between the work piece and the die and the difficulty of designing the die itself, the work piece must also be passed through the die several times before the desired shape or form is obtained.
Of course, this requires an advanced level of expertise and experience backed by careful thought.

Item Cold Forging Hot Forging
Work temperature during forming Room temperature High temperature
Work hardness during forming Hard Relatively soft
Forming pressure High pressure required Relatively low (preferable)
Work precision after forging High precision is possible Cannot be used when high precision is required
Work size Suited for smaller work pieces Can be used with large work pieces
Work surface roughness after forging Not rough Rough
Difference between work and die hardness Small Relatively high
Manufacturing diffulty Difficult Relatively easy
Forging passes until completion Many Few
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