API St 20H-2015 pdf free download
API St 20H-2015 pdf free download.Heat Treatment Services—Batch Type for Equipment Used in the Petroleum and Natural Gas Industry.
1 Scope 1.1 Purpose This standard specifies requirements for the qualification of suppliers of heat treatment services used in the manufacture of equipment for the petroleum and natural gas industries. 1.2 Applicability This standard is applicable to suppliers providing heat treatment services where API product standards require such services or otherwise specified as a requirement for conformance. The requirements of this standard apply to batch heat treatment operations that establish or affect the final mechanical properties and include stress relief operations. This standard applies to carbon steel, low-alloy steel, stainless steel, and nickel-base alloys. Case hardening, induction hardening, and flame hardening are not covered by this standard. 1.3 Heat Treatment Specification Levels (HSLs) This standard establishes the requirements for three heat treatment specification levels (HSLs). These HSL designations define different levels of heat treatment technical, quality, and qualification requirements. 2 Normative References The following referenced document is indispensable for the application of this standard. For undated references, the latest edition of the referenced document, including any amendments, apply. SAE AMS2750 1 , Pyrometry 3 Terms, Definitions, Acronyms, and Abbreviations For purposes of this standard, the following terms, definitions, and acronyms apply. 3.1 Terms and Definitions 3.1.1 acceptance criteria Defined limits placed on characteristics of materials, processes, products, or services. 3.1.2 case hardening A generic term covering several processes applicable to steel that change the chemical composition of the surface layer by absorption of carbon, nitrogen, or a mixture of the two and, by diffusion, create a concentration gradient. The result is a thin layer on the surface that is harder than the metal beneath it. The processes commonly used are carburizing and quench hardening, cyaniding, nitriding, and carbon nitriding.
3.1.4 flame hardening A process for hardening the surfaces of hardenable ferrous alloys in which an intense flame is used to heat the surface layers above the upper transformation temperature, whereupon the work-piece or area of the surface that has been heated by direct flame impingement is immediately quenched. 3.1.5 heat sink Metal of a defined cross section and similar heat transfer characteristics to the part(s) being heat treated and used to monitor the heat treatment temperature by the use of an embedded thermocouple. 3.1.6 induction hardening A surface hardening process in which only the surface layer of a suitable ferrous work-piece is heated by electromagnetic induction to a temperature above the upper critical temperature and immediately quenched. 3.1.7 marking Identification placed on the heat-treated material in accordance with this standard. 3.1.8 on-site activity Activity performed at the heat treatment supplier’s facility. 3.1.9 receiving verification Inspection and review of incoming material and attendant documentation. 3.1.10 working zone Usable volume of a furnace as determined by the temperature uniformity survey. 3.2 Acronyms and Abbreviations HSL heat treatment specification level MPS manufacturing process specification SAT system accuracy test TUS temperature uniformity survey 4 Heat Treatment Supplier Qualification 4.1 General This standard establishes requirements for three heat treatment specification levels (HSLs) and four processing classes. The heat treatment supplier may qualify to one or more of the processing classes listed in Table 1 and one or more HSLs. The following paragraphs describe the conditions that, when met, allow the heat treatment supplier to receive the appropriate HSL classification level.
