ASTM Standards for Steel Plates for Pressure Vessels

---

Introduction to ASTM A20-85

Standard designation A20-85 establishes common requirements that apply to rolled steel plates for pressure vessels under numerous ASTM specifications. These requirements govern unless otherwise specified in individual material specifications. The standard also includes supplementary requirements for additional testing or inspection when desired by the purchaser.

Appendix X2 of the standard describes the production and characteristics of coiled products that may be used for pressure vessel plates. In case of conflicting requirements, the individual material specification takes precedence over this general specification.

Purchasers may specify additional requirements that don't contradict the provisions of this general specification or individual material specifications. Such additional requirements must be included in the order information and are subject to negotiation with the supplier.

Generally, all materials covered by these specifications are intended to be suitable for fusion welding.

ASTM Specifications for Pressure Vessel Plates

The following table lists the ASTM specifications covered by standard designation A20-85:

Table 1. ASTM Specifications for Pressure Vessel Plates

Title of Specification	ASTM Designation
Pressure Vessel Plates, Alloy Steel, Chromium-Manganese-Silicon	A202
Pressure Vessel Plates, Alloy Steel, Nickel	A203
Pressure Vessel Plates, Alloy Steel, Molybdenum	A204
Pressure Vessel Plates, Alloy Steel, Manganese-Vanadium	A225
Pressure Vessel Plates, Carbon Steel, Low and Intermediate-Tensile Strength	A285
Pressure Vessel Plates, Carbon Steel, Manganese-Silicon	A299
Pressure Vessel Plates, Alloy Steel, Manganese-Molybdenum and Manganese- Molybdenum-Nickel	A302
Pressure Vessel Plates, Alloy Steel, 9 Percent Nickel Double-Normalized and Tempered	A353
Pressure Vessel Plates, Alloy Steel, Chromium- Molybdenum	A387
Pressure Vessel Plates, Carbon Steel, Improved Transition Properties	A442
Pressure Vessel Plates, Carbon Steel, High Strength Manganese	A455
Pressure Vessel Plates, Carbon Steel, for Intermediate-and Higher Temperature Service	A515
Pressure Vessel Plates, Carbon Steel, Moderate-and Lower- Temperature Service	A516
Pressure Vessel Plates, Alloy Steel, High Strength, Quenched and Tempered	A517
Pressure Vessel Plates, Alloy Steel, Quenched and Tempered, Manganese-Molybdenum and Manganese- Molybdenum-Nickel	A533
Pressure Vessel Plates, Heat-Treated, Carbon Manganese-Silicon Steel	A537
Pressure Vessel Plates, Alloy Steel Precipitation Hardening 18 Percent Nickel	A538
Pressure Vessel Plates, Alloy Steel, Quenched and Tempered Chromium-Molybdenum	A542
Pressure Vessel Plates, Alloy Steel, Quenched and Tempered Nickel-Chromium-Molybdenum	A543
Pressure Vessel Plates, Alloy Steel, Quenched and Tempered 8 and 9 Percent Nickel	A553
Pressure Vessel Plates, Carbon steel, Manganese-Titanium for Glass or Diffused Metallic Coatings	A562
Pressure Vessel Plates, Alloy Steel, Precipitation-Hardening 12 Percent Nickel	A590
Pressure Vessel Plates, Alloy Steel, Quenched and Tempered Nickel-Cobalt- Molybdenum- Chromium	A605
Pressure Vessel Plates, Carbon Steel, High Strength, for Moderate-and Lower- Temperature Service	A612
Pressure Vessel Plates, Five Percent Nickel Alloy steel, Specially Heat Treated	A645
Pressure Vessel Plates, Alloy Steel, 36 Percent Nickel	A658
Pressure Vessel Plates, Carbon-Manganese, for Moderate and lower Temperature Service	A662
Pressure Vessel Plates, Carbon Steel, Quenched and Tempered, for Welded Layered Pressure Vessels	A724
Pressure Vessel Plates, Alloy Steel and High-Strength Low-Alloy Steel, Quenched and Tempered	A734
Pressure Vessel Plates, Low-Carbon, Manganese-Molybdenum-Columbium Alloy Steel, for Moderate and Lower Temperature Service	A735
Pressure Vessel Plates, Low-Carbon Age-Hardening Nickel-Copper-Chromium- Molybdenum-Columbium Alloy Steel	A736
Pressure Vessel Plates, High-Strength Low-Alloy Steel	A737
Pressure Vessel Plates, Heat-Treated, Carbon-Manganese-Silicon Steel, for Moderate and Lower Temperature Service	A738
Pressure Vessel Plates, Quenched and Tempered, Manganese Chromium- Molybdenum-Silicon-Zirconium Alloy Steel	A782

Manufacturing Processes for Pressure Vessel Plates

Unless otherwise specified in the material specification, steel for pressure vessel plates may be manufactured using various processes including open-hearth, basic-oxygen, electric-furnace, vacuum arc remelt (VAR), or electroslag remelt (ESR).

The steel may be cast in ingots or strand cast. When multiple heats are consecutively strand cast, they must be melted to the same steelmaking composition range. The heat number assigned to the cast product (slab) may remain unchanged until all of the steel in the slab is from the following heat.

For plates produced from strand-cast slabs, the reduction ratio of thickness from slab to plate must be a minimum of 3 to 1. Plates can be produced either as discrete cut lengths of flat product or from coils. Plates produced from coil refers to plates that have been leveled or flattened and cut to length from a coiled product and are furnished without heat treatment. Plates that undergo heat treatment (annealing, normalizing, normalizing-and-tempering, or quenching-and-tempering) after decoiling are considered discrete cut lengths of flat products.

Heat Treatment Requirements and Options

Heat treatment of pressure vessel plates may be performed by the manufacturer, processor, or fabricator unless otherwise specified in the material specification. When the material specification requires heat treatment to be performed by the purchaser or their agent, and the material is to be supplied in a condition other than that required by the material specification, this must be stated in the order.

When plates are ordered without the required heat treatment, the responsibility for conforming to the heat treatment requirements of the material specification falls to the purchaser. The heat treatment must be performed as specified in the material specification, though the purchaser may specify alternative heat treatment methods provided they don't conflict with the material specification requirements.

When normalizing is performed by the fabricator, it may be accomplished during the heating process for hot forming. The temperature for hot forming should not significantly exceed the normalizing temperature.

If no heat treatment is required, the manufacturer or processor may optionally heat treat the plates by normalizing and then stress relieving to meet the material specification. With purchaser approval, cooling rates faster than those obtained by cooling in air are permissible to improve toughness, provided the plates are subsequently tempered in the temperature range from 595 to 705°C.