0.5Mo

The alloy with a nominal 0.5% molybdenum offers a significant improvement in high-temperature performance compared to carbon-manganese steels (C-Mn). It is widely used in the
fabrication of vessels and
pipelines requiring resistance to creep rupture and ductility at temperatures up to about 450 °C. The molybdenum content also enhances resistance to hydrogen attack, making it ideal for use in chemical processing plants. The mechanical properties of the weld metal, both in the as-welded and stress-relieved conditions, are excellent for welding technical structural and general structural steels intended for ambient or sub-zero temperature service. Therefore, these consumables are closely related to high-strength manganese-molybdenum alloy steels. Preheat and interpass temperatures generally range from 100 °C to 250 °C, depending on the thickness of the material being welded and the degree of restraint. Post-weld heat treatment (PWHT) for tempering can vary depending on the applied code; extremes range from 550 °C to 720 °C, with the most common range being from 630 °C to 670 °C. For materials up to 20 mm thick, some codes allow omitting the PWHT.

Ferritic creep resisting 0.5%Mo steels for elevated temperature service.

In the stress-relieved condition the microstructure consists of acicular ferrite with some tempered bainite.

• EN W.Nr.: 10028-2 gr. 16Mo3 (1.5415), 16Mo5 (1.5423), 10MnMo 4 5 (1.5424), 11MnMo 4 5 (1.5425), GS-22Mo 4 (1.5419)
• ASTM: A335 gr. P1, A209 & A 250 gr. T1, A336 gr. F1, A204 gr. A, B, C, A217 gr. WC1, A352 gr. LC1