JIS G 3203-1988 Alloy steel forgings for high temperature pressure vessels

JIS G 3203 : 1988 High Temperature Pressure Vessel Alloy Steel Forge Articles

Japan Industrial Standard (JIS) G 3203 : 1988 is for high temperature pressure vessel alloy steel forge articles. These forge articles are to be used for the production of pressure vessels, containers and tanks for use in high temperature applications. The JIS G 3203 : 1988 standard does not apply to forgings that are produced from pre- wrought alloys.

The forge articles covered by the standard are classified into four grades according to their tensile properties. Grade S1 is the highest grade and has the highest tensile strength and hardness. The range of chemical composition, mechanical properties and dimensional tolerances are given in the table below.

Chemical composition (maximum values of weight%)

Grade C Mn Si Cr Mo Ni V W P

S1 0.30 0.90 0.30 1.6 0.50 8.0 - - 0.03

Grade S2 0.35 0.90 0.30 1.5 0.30 5.5 0.05 0.05 0.03

Grade S3 0.40 1.00 0.40 1.4 0.30 3.0 0.05 0.05 0.03

Grade S4 0.45 1.10 0.50 1.3 0.30 2.0 - - 0.03

Mechanical properties

Grade Tensile strength (680- 800) MPa Tensile strength (overall) Tensile test Bend test Hardness

S1 680 - 800 480 - 540 Elongation (%) 24 HB max.

S2 640 - 760 440 - 510 Elongation (%) 26 HB max.

S3 590 - 710 400 - 470 Elongation (%) 28 HB max.

S4 560 - 680 370 - 440 Elongation (%) 30 HB max.

Dimensional tolerances

The maximum allowable tolerance on the size of the articles should be 0.3 mm in any dimension. All edges, corner and convex faces should be free from defects.

Testing and inspection

The forge articles should be inspected and tested in accordance with the provisions given in JIS G 3203 : 1988. The tests may include tensile test, bend test, macrostructure test and hardness test. The specimens should be taken from the center, near the surface and near the corner of the articles.

The forge articles should also be inspected visually or by other non-destructive means, such as X-ray, ultrasound or magnetic particle test.

Marking and identification

The forge articles should be marked clearly for identification. This marking should include the Japanese Industrial Standard (e.g. JIS G 3203 : 1988), grade, and the weight and batch number (or size/volume) of the article.

Conclusion

JIS G 3203 : 1988 is a standard for high temperature pressure vessels alloy steel forge articles. The forge articles are classified into four grades according to their tensile properties. Each grade has its own chemical composition and mechanical properties. The maximum allowable tolerance on the size should be 0.3 mm in any dimension. The forge articles must be inspected and tested in accordance with the standard, and it should be marked clearly for identification.

JIS G 3203-1988 High Temperature Pressure Vessel Alloy Steel Forging

This standard is a product of the Japan Industrial Standard (JIS) for High Temperature Pressure Vessel Alloy Steel Forging. It was established in 1988 to provide an accurate and consistent range of alloy steels for industrial use.

This standard is intended to produce metallic alloys using a variety of methods and processes for high temperature, pressure vessel applications. These processes include hot-forging, open-die-forging, closed-die-forging and ring-rolling. The JIS G 3203-1988 requirements encompass steel characteristics such as chemical composition, mechanical properties, hardenability, weldability and machinability. These characteristics are strictly adhering to the Japanese standard.

The JIS G 3203-1988 specifies the requirements for the use of alloy steels in the construction of high temperature, pressure vessels. Alloy steels play a significant role in various engineering and construction projects and have numerous advantages over other types of materials when used in these particular applications. Among these advantages are longer life span, higher strength, dimensional stability at elevated temperatures, excellent corrosion and wear resistant properties, durability and strength.

These alloy steels are further classified according to their chemical compositions. The JIS G 3203-1988 defines the 8 types of alloy steels, namely: 9-4-1 (low-alloy austenitic stainless steel), 9-4-2 (low-alloy ferritic stainless steel), 9-4-3 (heat-resistant austenitic stainless steel), 9-4-4 (austenitic heat resistant stainless steel), 9-4-5 (low-alloy ferritic), 9-4-6 (heat-resistant ferritic), 9-4-7 (austenitic martensite) and 9-4-8 (low-alloy martensite stainless steel).

The JIS G 3203-1988 requires that the alloy steel properties be tested according to this standard before application in any vessel or part in order to ensure the proper performance in operation. The main testing includes evaluations of tensile strength, chemical composition, impact toughness and elongation values. Further, the thermal treatment requirements in this standard are also strictly adhered to in order to ensure the desired properties of the alloy steel.

The JIS G 3203-1988 is a comprehensive standard for the production, specifications, and testing of alloy steels for high temperature, pressure vessels. It is paramount to ensure that this standard is strictly adhered to for any application of these alloy steels. By doing so, it will ensure the safety, performance, and quality of the vessels that are using these alloy steels.