1. **ASTM A790 vs. ASTM A928:**
* **ASTM A790:** Standard Specification for Seamless and Welded Ferritic/Austenitic Stainless Steel Pipe. It covers duplex stainless steel pipe (a mix of ferrite and austenite phases) intended for corrosive service, made by seamless or welding processes (without filler metal addition). It specifies chemical composition, mechanical properties, testing, and dimensional requirements.
* **ASTM A928:** Standard Specification for Ferritic/Austenitic (Duplex) Stainless Steel Pipe Electric Fusion Welded with Addition of Filler Metal. It specifically covers electric fusion welded duplex stainless steel pipe where filler metal is added during the welding process. It includes requirements for supplementary testing of the weld (like corrosion testing) beyond the base requirements of A790.
2. **ASTM C635:**
* **ASTM C635:** Standard Specification for the Manufacture, Performance, and Testing of Metal Suspension Systems for Acoustical Tile and Lay-in Panel Ceilings. It defines the requirements for the main runners, cross runners, wall angles, and other components that make up the metal grid system used to support suspended acoustical ceiling tiles and panels.
3. **ASTM C150:**
* **ASTM C150:** Standard Specification for Portland Cement. This fundamental specification covers the chemical and physical requirements for the eight main types of portland cement used in concrete and mortar construction (Types I, IA, II, IIA, III, IIIA, IV, and V). It sets criteria for composition, strength development, fineness, setting time, and soundness.
4. **ASTM D790:**
* **ASTM D790:** Standard Test Methods for Flexural Properties of Unreinforced and Reinforced Plastics and Electrical Insulating Materials. It describes procedures for determining the flexural (bending) properties of rigid and semi-rigid plastics, including the flexural modulus (stiffness) and flexural strength, using either a simple beam supported at two points (three-point bending) or a center-loaded beam supported at two points (four-point bending).
5. **ASTM C618:**
* **ASTM C618:** Standard Specification for Coal Fly Ash and Raw or Calcined Natural Pozzolan for Use in Concrete. It defines the chemical, physical, and performance requirements for materials like fly ash (from burning coal) and natural pozzolans (volcanic ash or diatomaceous earth) used as supplementary cementitious materials (SCMs) in concrete. These materials react with cement hydration products to improve concrete properties like workability, strength development, and durability. It categorizes them as Class F, Class C, or Class N.
