ASTM A638M-1995 High-Temperature Precipitation Hardening Iron-Based Supermartensitic Rods, Forgings, and Billets
ASTM A638M-1995 is an international standard for precipitating hardening iron-based supermartensitic rods, forgings and billets. This specification covers UNS S44600 and S44800 grade materiAns that are used at high temperatures in the temperature range of 900-1300°C. ASTM A638M-1995 defines the chemical, physical, mechanical and metallurgical properties for these materials.
Chemical Requirements:
The chemical requirements for ASTM A638M-1995 materials include the elements Carbon (C), Manganese (Mn), Silicon (Si), Chromium (Cr), Nickel (Ni), Molybdenum (Mo), Vanadium (V), Phosphorous (P), Sulfur (S), and Nitrogen (N). The maximum allowable levels for each element are as follows: C 0.08 max, Mn 2.40 max, Si 1.00 max, Cr 13.0-14.5, Ni 7.0-8.0, Mo 3.0-3.5, V 0.15-0.45, P 0.04 max, S 0.03 max, and N 0.2-0.25 max.
Physical Requirements:
The physical requirements for ASTM A638M-1995 materials include the following test methods: Charpy V-notch (CVN) impact test, Rockwell hardness test, density, electrical resistivity, magnetic permeability, and grain size. These tests evaluate material characteristics such as toughness, strength, resistance to wear, plasticity, ductility, and hardness.
Mechanical Requirements:
The mechanical requirements for ASTM A638M-1995 materials include the following tests: Tensile strength at room temperature, yield strength at room temperature, elongation in 2 inches, hardness, and Charpy V-notch impact test. The minimum and maximum allowable strength, toughness, and ductility values for these tests are provided in the document.
Metallurgical Requirements:
The metallurgical requirements for ASTM A638M-1995 materials include tests such as the X-ray diffraction (XRD) analysis, optical microscopy, scanning electron microscopy (SEM) analysis, metallography, optical metallography, and scanning electron microscopy (SEM) microstructure testing. These tests are used to evaluate the structure, composition, and microstructure of these materials.
Conclusion:
ASTM A638M-1995 is an international standard that covers the manufacture and testing of high-temperature precipitation hardening iron-based supermartensitic rods, forgings and billets. The specification includes detailed requirements for chemical composition, physical properties, mechanical properties, and metallurgical properties for these materials. Tests such as tensile strength, yield strength, elongation, hardness, and Charpy V-notch impact test are used to evaluate the mechanical properties of these materials. Metallurgical tests such as X-ray diffraction, optical microscopy, scanning electron microscopy, and metallography are also used to evaluate the structure, composition, and microstructure of these materials.
