1. **What does ASTM A240 mean?**
ASTM A240/A240M is a standard specification issued by ASTM International. It covers chromium, chromium-nickel, and chromium-manganese-nickel stainless steel plate, sheet, and strip used primarily for pressure vessels and general applications requiring good corrosion resistance. It defines the chemical composition, mechanical properties, heat treatment, and testing requirements for these materials.
2. **What is ASTM A240 steel equivalent to?**
There is no single, exact global equivalent for ASTM A240 grades due to different standardization systems. However, common *approximate* equivalents include:
* **European (EN):** Grades like 1.4301 (304), 1.4401 (316), 1.4541 (321), 1.4571 (316Ti) are often comparable to common A240 grades like 304, 316, 321, 316Ti respectively.
* **Japanese (JIS):** SUS304 (≈304), SUS316 (≈316), SUS321 (≈321), SUS316Ti (≈316Ti).
* **Chinese (GB):** 06Cr19Ni10 (≈304), 06Cr17Ni12Mo2 (≈316), 06Cr18Ni11Ti (≈321).
**Crucially:** Direct substitution is **not** automatic. Chemical composition ranges, mechanical properties, testing requirements, and application standards can differ. Always consult specific material standards and involve qualified engineers when considering material substitution.
3. **What is the difference between ASTM A182 and A240?**
The primary differences lie in the **product form** and **intended application**:
* **ASTM A182/A182M:** Covers **forged or rolled alloy and stainless steel pipe flanges, forged fittings, and valves and parts** for high-temperature service. It deals with *wrought* products that are subsequently forged into shape (flanges, fittings).
* **ASTM A240/A240M:** Covers **plate, sheet, and strip** of chromium, chromium-nickel, and chromium-manganese-nickel stainless steel. This material is used to fabricate components like pressure vessel shells or as base material for welded pipe/tubes (e.g., via ASTM A312).
**In essence:** A182 is for *forged fittings and flanges*, while A240 is for *flat rolled products (plate, sheet, strip)*. Both can cover similar alloy grades (e.g., F304 in A182 ≈ 304 in A240), but they govern different physical forms and manufacturing processes.
4. **What is an ASTM standard for steel pipe?**
There are *many* ASTM standards for steel pipe, each designed for specific materials, manufacturing methods, and applications. Key examples include:
* **A53/A53M:** Standard for black and hot-dipped galvanized, welded and seamless steel pipe for general mechanical and pressure applications.
* **A106/A106M:** Standard for seamless carbon steel pipe for high-temperature service (common in power plants and refineries).
* **A312/A312M:** Standard for seamless, welded, and heavily cold worked austenitic stainless steel pipe (common grades like 304, 316).
* **A335/A335M:** Standard for seamless ferritic alloy-steel pipe for high-temperature service (e.g., grades P5, P9, P11, P22, P91).
* **A500:** Standard for cold-formed welded and seamless carbon steel structural tubing in round and shapes.
* **A790/A790M:** Standard for seamless and welded ferritic/austenitic stainless steel pipe (Duplex grades like S31803, S32205).
5. **What is ASTM steel grade?**
An ASTM steel grade is a specific designation within an ASTM material standard that defines a particular type of steel with a defined chemical composition range and minimum mechanical properties. It acts as a shorthand identifier. For example:
* In A240: "304", "316L", "410S" are grades.
* In A106: "A", "B", "C" are grades (differing in carbon content and strength).
* In A572: "42", "50", "55", "60", "65" are grades (differing in yield strength).
