A method for producing a retort for a nitriding furnace, in which metallic workpieces are heat-treated in a pre-determined atmosphere, includes pickling at least the surfaces of the retort, which are configured to come into contact with the pre-determined atmosphere while the nitriding furnace is operating, by using a pickling agent. The pickled surfaces may then be electropolished and passivated. A retort may be produced according to this method and the retort may be used in a nitriding furnace.

An heat treatment apparatus for a vehicle body component includes, a jig base, a lower fixed die fixedly installed on the jig base and supporting the vehicle body component that is press-molded into a predetermined shape, a heating unit installed on the lower fixed die and locally heating the vehicle body component, a plurality of side movable dies that can move reciprocally disposed at both sides of the lower fixed die, installed on the jig base, and selectively combinable with the lower fixed die, a cooling unit installed on each side movable die and cooling a heating portion of the vehicle body component, and an upper movable die that can move reciprocally in the up and down direction correspondingly to the lower fixed die, and configured to clamp the vehicle body component through the lower fixed die and at least one of the side movable dies combined together.

Uniform hardenability is achieved in plastic injection mold and die block tooling of 20 inches and larger by the use of 0.05-0.20 vanadium in conjunction with low carbon steel in which ingots are hot worked to form mold and die blocks having cross sections of 20 inches and larger followed by water quenching and tempering.

A method for manufacturing a tow hook assembly begins with heating a first steel blank to within a range of 2200° F. and 2300° F. to create a first heated steel blank. A second steel blank is heated to within the range of 2200° F. at 2300° F. to create a second heated steel blank. The first heated steel blank is forged into a tow hook. The second heated steel blank is forged into a flange plate. The tow hook in the flange plate are welded together to form the tow hook assembly. This method reduces waste by minimizing the size of the first and second steel blanks.

A thin gauge wear-resistant steel sheet, including the following chemical elements expressed in percentage by weight: 0.15-0.20 wt. % of carbon; 1.2-1.8 wt. % of manganese; 0.1-0.40 wt. % of copper; 0.15-0.30 wt. % of molybdenum; 0.20-0.40 wt. % of chromium; 0.03-0.06 wt. % of niobium; 0.01-0.03 wt. % of titanium; 0.0006-0.0015 wt. % boron; less than 0.015 wt. % of phosphorus; less than 0.010 wt. % of sulphur; and the balance being ferrum and unavoidable impurities, wherein the thickness of the steel sheet is in a range of 3.0 to 8 mm.

A member (10), for bearing a load, including a load receiving portion (12) at which the load is applicable to the member. A strainable portion (14) is connected to the load receiving portion to be strained by the load. A datum (16a) is defined and an elongate portion (18) defines another datum (18a). The datums are arranged such that relative displacement therebetween indicates an amount by which the strainable portion is strained. The strainable portion defines the datum.

An aspect of the present disclosure relates to a high-strength steel material having enhanced resistance to crack initiation and propagation at low temperature.

There are provided an apparatus for cooling a rail and a method for manufacturing a rail, capable of inexpensively manufacturing a rail with high hardness and high toughness. The apparatus for cooling a rail, configured to jet a cooling medium to the head portion and foot portion of a rail in an austenite temperature range to forcibly cool the rail, includes: a first cooling unit including plural first cooling headers configured to jet the cooling medium as gas to the head top face and head side of the head portion, and first driving units configured to move at least one first cooling header of the plural first cooling headers to change the jet distance of the cooling medium jetted from the first cooling header; and a second cooling unit including a second cooling header configured to jet the cooling medium as gas to the foot portion.

To provide a steel for bolts with excellent delayed fracture resistance and cold forgeability while maintaining the strength as a steel material, and also to provide a bolt producing from such a steel for bolts.

The steel for bolts according to the present invention includes, in percent by mass: 0.20 to 0.40% of C; 1.5 to 2.5% of Si; 0.20 to 1.5% of Mn; more than 0% and 0.03% or less of P; more than 0% and 0.03% or less of S; 0.05 to 1.5% of Cr; 0.01 to 0.10% of Al; 0.0003 to 0.01% of B; 0.002 to 0.020% of N; and one or two elements selected from the group consisting of 0.02 to 0.10% of Ti and 0.02 to 0.10% of Nb, with the balance being iron and inevitable impurities.

To provide a steel for bolts with excellent delayed fracture resistance and cold forgeability while maintaining the strength as a steel material, and also to provide a bolt producing from such a steel for bolts.

The steel for bolts according to the present invention includes, in percent by mass: 0.20 to 0.40% of C; 1.5 to 2.5% of Si; 0.20 to 1.5% of Mn; more than 0% and 0.03% or less of P; more than 0% and 0.03% or less of S; 0.05 to 1.5% of Cr; 0.01 to 0.10% of Al; 0.0003 to 0.01% of B; 0.002 to 0.020% of N; and one or two elements selected from the group consisting of 0.02 to 0.10% of Ti and 0.02 to 0.10% of Nb, with the balance being iron and inevitable impurities.