15CrMoG High-Pressure Alloy Tube: Properties, Uses and Welding

Above roughly 450 °C, plain carbon steel begins to creep and scale, and tube walls thin out silently until a burst. The 15CrMoG high-pressure alloy tube was developed exactly for this window — a chromium-molybdenum steel that holds strength and oxidation resistance in boilers, superheaters and refinery heaters.

What 15CrMoG Is

15CrMoG is a Chinese GB 5310 grade of low-alloy heat-resistant steel, broadly equivalent to ASTM A335 P12 / 15CrMo and DIN 13CrMo44. With about 1% chromium and 0.5% molybdenum, it gains creep strength and graphitisation resistance while remaining weldable under a qualified procedure.

Chemical and Mechanical Profile

• Typical composition: C 0.12–0.18%, Si 0.17–0.37%, Mn 0.40–0.70%, Cr 0.80–1.10%, Mo 0.40–0.55%

• Tensile strength commonly 440–640 MPa with yield around ≥ 235 MPa

• Delivery condition: normalised and tempered, which stabilises the microstructure for long-term high-temperature duty

• Supplied to GB/T 5310, with ASTM/DIN equivalents available for export projects

Where It Performs Best

• Superheater and reheater tube bundles in power boilers

• High-pressure steam headers, main steam and hot reheat piping

• Refinery heater tubes, coker and hydrotreater circuits

• Petrochemical reformer and heat-exchanger tubing

• High-temperature process piping in chemical and fertiliser plants

Welding and Heat Treatment

Weld 15CrMoG with matching filler, apply preheat (typically 150–200 °C) and post-weld heat treatment around 680–720 °C to temper the heat-affected zone. Skipping PWHT is a frequent cause of HAZ cracking and premature creep failure in service.

Inspection Delivered with the Order

Zhantong supplies EN 10204 3.1 / 3.2 certificates, chemical and mechanical test reports, ultrasonic and eddy-current testing, hydrostatic testing, dimensional records and third-party witness inspection on request for every 15CrMoG shipment.

Frequently Asked Questions

What is the difference between 15CrMoG and 12Cr1MoVG?

12Cr1MoVG adds vanadium, raising creep strength and allowable temperature. 15CrMoG suits medium-temperature superheaters; 12Cr1MoVG is chosen for hotter headers and main steam.

Is 15CrMoG weldable?

Yes, with preheat and PWHT. Always follow a qualified WPS/PQR and control interpass temperature.

Can it be supplied cold drawn?

Yes for heat-exchanger and precision applications, though hot-finished is normal for boiler duty.

Conclusion

For high-pressure, medium-to-high temperature steam and process service, 15CrMoG delivers proven creep resistance at a sensible cost. Zhantong stocks and produces 15CrMoG alloy tube to GB, ASTM and DIN equivalents with full certification. Send design temperature, pressure and size for a technical quotation.