A martensitic stainless steel containing, by mass %, C: 0.20% to 0.40%, N: 0.1% or less, Mo: 3% or less, and Cr: 12.0% to 16.0%, such that 0.3%C+N0.4% and a PI value (=Cr+3.3 Mo+16 N) is 18 or more, with the remainder being substantially Fe and unavoidable impurities is quenched from a temperature of 1,030 C. to 1,140 C. and subjected to a subzero treatment and tempering so as to obtain a prior austenite crystal grain size of a surface layer of 30 m to 100 m and a surface hardness of 58 HRc to 62 HRc.

A process for reducing flatness deviations in an alloy article is disclosed. An alloy article may be heated to a first temperature at least as great as a martensitic transformation start temperature of the alloy. A mechanical force may be applied to the alloy article at the first temperature. The mechanical force may tend to inhibit flatness deviations of a surface of the alloy article. The alloy article may be cooled to a second temperature no greater than a martensitic transformation finish temperature of the alloy. The mechanical force may be maintained on the alloy article during at least a portion of the cooling of the alloy article from the first temperature to the second temperature.

A process for reducing flatness deviations in an alloy article is disclosed. An alloy article may be heated to a first temperature at least as great as a martensitic transformation start temperature of the alloy. A mechanical force may be applied to the alloy article at the first temperature. The mechanical force may tend to inhibit flatness deviations of a surface of the alloy article. The alloy article may be cooled to a second temperature no greater than a martensitic transformation finish temperature of the alloy. The mechanical force may be maintained on the alloy article during at least a portion of the cooling of the alloy article from the first temperature to the second temperature.

An article, for example a turbomachinery article is presented. The article includes a weldable first component having a base portion and a flange portion. The flange portion is outwardly projecting normal to a surface of the base portion; and is joined with the base portion by a solid state joint. The base portion comprises a nanostructured ferritic alloy; and the flange portion comprises a steel substantially free of oxide nanofeatures. The first component is joined to a second component through the flange portion of the first component by a weld joint.

Steel plungers for hydraulic fracturing pumps having enhanced surface hardness properties, preferably made of alloyed steel and a method for manufacturing said plungers, comprising an ion nitriding process.

Provided are a chain component that has a simple surface treatment structure and can maintain good wear resistance over a long time, and a chain that includes the chain component and maintains good wear elongation resistance. The chain component of a power transmission chain for industrial use includes a chromium nitride layer formed on an outer side of a steel base material and containing more than 0 mass % but not more than 55 mass % iron. At least a surface of the chromium nitride layer that slides against other components is a rough surface with peaks and valleys.

This invention pertains to plastic injection mold tooling, and also large forgings, formed from a low carbon mold steel having markedly increased hardening and hardenability properties in large sections as contrasted to currently available commercial products. The above attributes are obtained together with equal or better machinability and improved mold parting line wear. When manufactured in conjunction with a double melt process, this invention can improve significantly polishing characteristics and other attributes of molded parts in tooling sets.

In a method for increasing steel impact toughness, the steel composition contains from about 5 wt % to about 10 wt % manganese and has a martensite finish temperature (M.sub.f) below room temperature. The steel composition is exposed to hot forming to form a steel part. During hot forming, the steel composition is subjected to a heat treatment temperature above its fully austenite formed temperature, is transferred to a die, and while in the die, is simultaneously formed and quenched. In one example, quenching cools the steel composition to room temperature, and the steel part is removed from the die and reheated to a baking temperature ranging from about 120 C. to about 400 C. In another example, quenching is interrupted at an interruption temperature ranging from about 120 C. to about 400 C., and the steel composition is maintained at the interruption temperature for a predetermined time and then is cooled to room temperature.

This invention relates to a steel sheet provided with a sacrificial cathodic protection layer comprising from 5 to 50% zinc by weight, from 0.1 to 15% silicon by weight and optionally up to 10% magnesium by weight and up to 0.3% by weight, in cumulative content, of additional elements, and also comprising a protection elements to be selected from among tin in a percentage by weight between 0.1 and 5%, indium in a percentage by weight between 0.01 and 0.5% and combinations thereof, the balance consisting of aluminum and residual elements or unavoidable impurities. The invention further relates to a method for the fabrication of parts by hot or cold stamping and the parts that can be thereby obtained.

The high-strength steel for steel forgings according to the present invention has a composition that includes, as basic components, C: 0.35 mass % to 0.47 mass %; Si: 0 mass % to 0.4 mass %; Mn: 0.6 mass % to 1.5 mass %; Ni: more than 0 mass % up to 2.0 mass %; Cr: 0.8 mass % to 2.5 mass %; Mo: 0.10 mass % to 0.7 mass %; V: 0.035 mass % to 0.20 mass %; Al: 0.015 mass % to 0.050 mass %; N: 30 ppm to 100 ppm, and O: more than 0 ppm up to 30 ppm, the balance being Fe and inevitable impurities. The metal structure is mainly bainite, martensite or a mixed structure of bainite and martensite. Among cubic B1-type precipitates, the number of coherent precipitates having a diameter equal to or smaller than 30 nm is equal to or smaller than 50/m.sup.2.