Chemical Composition and Mechanical Properties of Heat Resistant Steel Bars According to JIS G 4311-1991
Heat-resistant steel bars are components used within power plants and industrial boilers that are produced and nominally certified in accordance with JIS G 4311-1991, the Standard of the Japanese Industrial Standard. These steel bars are process-resistant and display an extraordinary strength while under high temperatures. While manufacturing them, a strict observance of alloying elements, and tensile properties is also instituted. The chemical properties, as well as the mechanical properties of heat-resistant steel bars manufactured in accordance to JIS G 4311-1991, are considered in this article.
Chemical Properties
The chemical composition requirements of heat-resistant steel bars made in accordance to JIS G 4311-1991 are listed in Table 1 below.
Table 1: Chemical Composition Requirements
C: 0.20% max
Si: 1.30% max
Mn: 0.30%-2.00%
P: 0.030% max
S: 0.030% max
Ni: 1.50%-3.00%
Cr: 1.50%-3.00%
Mo: 0.50%-1.50%
Ti: 0.20% max
Al: 0.10% min
Cu: 0.30% max
V: 0.10%-0.20%
N: 0.20% max
B: 0.020% max
The chemical compositions listed above are general for heat-resistant steel bars that are made in accordance to JIS G 4311-1991, though there may be slight differences in the components depending on the process used for manufacturing the bars.
Mechanical Properties
The mechanical properties of heat-resistant steel bars manufactured under JIS G 4311-1991 are usually displayed in Tables 2, 3, and 4.
Table 2: Tensile Strength Requirements
Yield Strength Rp0.2 (MPa): ≥470
Tensile Strength Rm (MPa): ≥630
Elongation A (L0=50mm): ≥18
Table 3: Hardness Requirements
Brinell Hardness HBW10/3000: ≥274
Table 4: Impact Strength Requirements
Charpy V-Notch Impactive Strength KV (J): ≥35
Conclusion
Heat-resistant steel bars are components used in many industrial applications and manufactured according to JIS G 4311-1991. The chemical properties must meet strict requirements as set out in the standard, and the mechanical properties must achieve specific values for tensile strength, hardness, and impact strength. The requirements listed within the standard are what guarantee the high quality of these steel bars and allow them to be used in extreme high-temperature conditions.
