Technical Regulation and Scope of Application for ASTM/ASME A/SA 668M
The ASTM/ASME A/SA 668M standard defines technical requirements for carbon and alloy steel forgings, both in untreated and heat-treated conditions, intended for general industrial use. This specification covers a range of products not covered by highly specialized standards for pressure vessels, railway equipment, turbogenerator components, high-strength fasteners, or gears operating in specific temperature environments.
It is important to note that the standard does not apply to merchant bars (hot-rolled or cold-drawn bars).
The classification of forgings according to the standard includes six grades of carbon steel and seven grades of alloy steel. The choice of a specific class determines the parameters of heat treatment and the normative mechanical property indicators of the material.
For products marked with the “H” index, certification and mandatory acceptance are carried out only upon successful completion of hardness tests. EV Group China ensures strict control of product compliance with these requirements.
The specification provides for the possibility of applying additional requirements described in the A788/A788M standard, which are implemented exclusively at the customer’s request. Appendix X1 provides a correlation of current classes with historical specifications A235, A237, and A243, which have been completely replaced by this standard.
Technical indicators are presented in two independent systems: SI and inch-pound. According to the requirements of the standard, the systems are not interchangeable, so when calculating and ordering products from EV Group China, it is necessary to adhere to one selected system. In the absence of an indication of the “M” index in the order specification, delivery is carried out in inch-pound units of measurement.
The development of the standard was carried out in full compliance with the international standardization principles of the WTO, which guarantees high quality and predictability of the physical and mechanical characteristics of the forgings supplied by EV Group China.