EN10216-2 15NiCuMoNb5-6-4 (DIWA 373, WB36) High Pressure Boiler Tube
15NiCuMoNb5-6-4 steel grade is one of grade in EN 10216-2, it is widely used in large diameter seamless high pressure boiler tubes
15NiCuMoNb5-6-4 (DIWA 373, 15NiCuMoNb5, or WB36) is a high-temperature, high-strength, high-strength, high-strength structural steel developed by Germany in the 1930s. The steel is alloyed with several alloying elements such as Ni-Cu-Mo-Nb, which not only greatly improves the high temperature strength and temperature of the steel, but also has good comprehensive mechanical properties and hot workability. And solderability.
15NiCuMoNb5-6-4 (WB36) high pressure boiler tubes are manufactured by seamless process.
Chemical composition of 15NiCuMoNb5-6-4
The supply condition of 15NiCuMoNb5-6-4 (DIWA 373, WB36) steel pipe is normalizing (quenching) + tempering. After the final heat treatment of normalizing + tempering,
The metallographic structure is bainite + ferrite + sorbite or bainite + a small amount of ferrite.
Mechanical properties of 15NiCuMoNb5-6-4
||Impact work longitudinal/J
Durable strength σ, 15NiCuMoNb5-6-4 (WB36) high pressure boiler tube
|Normalizing or quenching
||Stress relief heat treatment
|900-980 ° C air cooling
||580-640 ° C air cooling
||550-600 ° C air cooling
|880-930 ° C oil or water cooling
||620-700 ° C air cooling
The temperature for the stress relief treatment should be 30 ° C lower than the actual tempering temperature.
The heating of the steel pipe should be carried out completely and thoroughly. When the steel tube is heated to the quenching temperature, the holding time is 1 minute per mm / (wall thickness is less than 20 mm, at least 20 minutes). The tempering and stress-relieving holding time is calculated according to the wall thickness of 2 minutes per mm, and the minimum is not less than 30 minutes.
EN10216-2 15NiCuMoNb5-6-4 steel pipe has good welding performance. Manual welding electrode L-80 (AWS-E11016G), tungsten argon arc welding wire with SMH-80 (AWS-E110S) or the corresponding domestic welding materials. In order to avoid welding cracks, preheating is required before welding (temperature is 150-200 ° C). De-stressing treatment after welding.
WB36 has good solderability. The cold crack is more sensitive, but preheating at 150 °C can prevent cold cracks and is not sensitive to reheat cracks. Manual arc welding with electrode CHE607NI base H10Mn2NiMoA/H08Mn2MoA welding wire with SJ101 flux submerged arc automatic welding, after 530-600 °C post-weld heat treatment has good performance, can meet the manufacturing requirements.