The present invention relates to one or more rust-proof springs for use in a firearm assembly. The rust-proof springs involve a variety of metals combined to create an alloy that does not react with moisture to form rust. The alloy is formed into one or more mechanical coil springs, and the mechanical coil springs are heat treated to improve the structural strength of the springs. The advantage of the rust proof springs for use in the firearm assembly is that the firearms can be exposed to moisture, such as moisture from rain, and the firearm user would not have to worry about rust on the firearm springs later causing issues with the firearm working as intended. Additionally, the one or more springs have high heat resistance properties.

Apparatus is provided for metallurgical heat treatment of coil springs, or similarly shaped workpieces and articles of manufacture, by electric resistance heating along the entire length of the workpiece so that the ends of the workpiece can be heat treated to the same degree and quality as the section of the workpiece between its two ends.

Apparatus is provided for metallurgical heat treatment of coil springs, or similarly shaped workpieces and articles of manufacture, by electric resistance heating along the entire length of the workpiece so that the ends of the workpiece can be heat treated to the same degree and quality as the section of the workpiece between its two ends.

A method of heat-treating an additively-manufactured ferromagnetic component is presented and a related ferromagnetic component is presented. A saturation flux density of a heat-treated ferromagnetic component is greater than a saturation flux density of an as-formed ferromagnetic component. The heat-treated ferromagnetic component is further characterized by a plurality of grains such that at least 25% of the plurality of grains have a median grain size less than 10 microns and 25% of the plurality of grains have a median grain size greater than 25 microns.

A method of heat-treating an additively-manufactured ferromagnetic component is presented and a related ferromagnetic component is presented. A saturation flux density of a heat-treated ferromagnetic component is greater than a saturation flux density of an as-formed ferromagnetic component. The heat-treated ferromagnetic component is further characterized by a plurality of grains such that at least 25% of the plurality of grains have a median grain size less than 10 microns and 25% of the plurality of grains have a median grain size greater than 25 microns.

A wire rod for springs with improved toughness and corrosion fatigue properties is disclosed. The disclosed wire rod comprises by weight percent, carbon (C): 0.4 to 0.7%, silicon (Si): 1.2 to 2.3%, manganese (Mn): 0.2 to 0.8%, chromium (Cr): 0.2 to 0.8%, and a balance of Fe and inevitable impurities, and a grain size is 13.2 μm or less, and a Charpy impact energy value is 38 J/cm.sup.2 or more.

A wire rod for springs with improved toughness and corrosion fatigue properties is disclosed. The disclosed wire rod comprises by weight percent, carbon (C): 0.4 to 0.7%, silicon (Si): 1.2 to 2.3%, manganese (Mn): 0.2 to 0.8%, chromium (Cr): 0.2 to 0.8%, and a balance of Fe and inevitable impurities, and a grain size is 13.2 μm or less, and a Charpy impact energy value is 38 J/cm.sup.2 or more.

A martensitic stainless steel sheet has a composition containing, (mass %), from 0.10 to 0.15% of C, from 0.05 to 0.80% of Si, from 0.05 to 2.00% of Mn, 0.040% or less of P, 0.003% or less of S, from 0.05 to 0.50% of Ni, from 11.0 to 15.0% of Cr, from 0.02 to 0.50% of Cu, from 0.005 to 0.06% of N, from 0.001 to 0.20% of Al, from 0 to 1.00% of Mo, from 0 to 0.50% of V, from 0 to 0.01% of B, balance Fe and unavoidable impurities. An M value=420C−11.5Si+7Mn+23Ni−11.5Cr−12Mo−10V+9Cu−52Al+470N+189 is 100 or more. A carbonitride number density having a circle equivalent diameter of 1.0 μm or more is 15.0 or less per 0.01 mm.sup.2. 0.2% yield strength is 1,100 N/mm.sup.2 or more.

The invention relates to a steel wire suitable for making a spring or medical wire products which remarkably improve the performance of conventional stainless steel wire. The steel comprises (in wt. %): C: 0.02 to 0.15, Si: 0.1 to 0.9, Mn: 0.8 to 1.6, Cr 16 to 20, Ni: 7.5 to 10.5, Mo: ≤3, Al: 0.5 to 2.5, Ti: ≤0.15, N: ≤0.05, optional elements, and impurities, balance Fe, wherein the total amount of Cr and Ni is 25 to 27 wt. %, and wherein the steel has a microstructure including, in volume % (vol. %), martensite: 40 to 90, austenite: 10 to 60, and delta ferrite: ≤5.

A spring steel having a superior fatigue life, and a manufacturing method for the same. The chemical components thereof are as follows in weight percentage: C: 0.52-0.62%, Si: 1.20-1.45%, Mn: 0.25-0.75%, Cr: 0.30-0.80%, V: 0.01-0.15%, Nb: 0.001-0.05%, N: 0.001-0.009%, O: 0.0005-0.0040%, P: ≤0.015%, S: ≤0.015%, and Al: ≤0.0045%, with the remainder being Fe and incidental impurities, wherein the following condition is also met 0.02≤(2Nb+V)/(20N+C)≤0.40. The spring steel of the present invention has a microstructure of tempered troostite+tempered sorbite, a prior austenite grain size less than 80 um, a size of alloy nitride and carbide precipitates being 5-60 nm, and a maximum width of single-grain inclusions being less than 30 pm. The spring steel has a handling strength greater than 2020 MPa, superior ductility and toughness (the reduction of area≥40%), and a fatigue life≥800,000 times, thereby meeting application requirements of high-stress springs in industries, such as automobiles, machinery, and the like.