API St 20H-2015 pdf 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.
4.3 Heat Treatment Specification Levels 4.3.1 Heat Treatment Specification Level 1 (HSL-1) 126.96.36.199 The pyrometric requirements for heat treatment equipment in conformance with HSL-1 shall be in accordance with 8.2. 188.8.131.52 A temperature uniformity survey (TUS) shall be performed every 12 months minimum for the full temperature operating range of the furnace in accordance with 8.2. 184.108.40.206 The heat treatment supplier shall record the quench media temperature at start, peak, and finish of the quench cycle. Records shall be maintained. 4.3.2 Heat Treatment Specification Level 2 (HSL-2) The requirements of HSL-1 apply with the following modifications. 220.127.116.11 A TUS shall be performed every six months minimum for the full temperature operating range of the furnace in accordance with 8.2. 18.104.22.168 Quench media temperature shall be recorded during the entire quench process. Records shall be maintained. 22.214.171.124 Additional temperatures shall be added to the TUS, as required, to ensure that no two adjacent survey temperatures are greater than 600 °F (335 °C) apart. 126.96.36.199 Thermocouples shall be verified for accuracy or replaced at least every three months, in accordance with the heat treatment supplier’s written procedure. Records shall be maintained. 4.3.3 Heat Treatment Specification Level 3 (HSL-3) 188.8.131.52 The pyrometric requirements for heat treatment equipment in conformance with HSL-3 shall be in accordance with 8.3. 184.108.40.206 Quench media temperature shall be recorded during the entire quench process. Records shall be maintained.
5 Responsibilities and Duties It is the responsibility of the heat treatment supplier to ensure that it: — performs all heat treatment in accordance with specified standards and applicable quality control criteria; — performs only heat treatment for which it is adequately equipped and staffed; — performs only heat treatment for which its employees are adequately qualified; — assures equipment is calibrated and personnel are qualified in accordance with the requirements of the supplier’s written procedure; — assures facility and equipment is properly maintained; — informs the purchaser of any discrepancy or limitation imposed on the requested heat treatment by such factors as size, traceability, form, shape, material, or procedure; — calls to the attention of the purchaser any irregularity or deficiency noted in the procurement documents; — promptly submits formal reports of all heat treatment to the purchaser; and — informs the purchaser of noncompliance of the specified standards or procurement document requirements. 6 Personnel Training Requirements Personnel performing heat treatment shall be trained and qualified in accordance with requirements of the heat treatment supplier’s written procedure. Records of training and qualification shall be maintained. 7 Heat Treatment Facility Capability 7.1 General The heat treatment supplier shall complete and maintain a current list of equipment used in heat treatment to this standard. The required data and a sample data format are listed in Annex A.