What is the difference between 20MnHR-BR and 20MnHR-B steel

20MnHR-BR and 20MnHR-B are steels for nuclear power and are one grade. 20MnHR-B steel has good toughness and weldability.

20MnHR-BR/20MnHR-B steel chemical composition:
C≤0.20; Si: 0.20-0.50; Mn1.00-1.60; P≤0.015; S≤0.012; Mo≤0.15; Cr≤0.25; Cu≤0.28; Cu+6Sn≤0.33; Nb≤0.040; V≤0.050; Ni≤0.30.

20MnHR-BR/20MnHR-B steel delivery status: normalized.

20MnHR-BR/20MnHR-B steel production process: steel is smelted by electric furnace or electric furnace + out-of-furnace refining method, and sedative pouring is adopted.

20MnHR-BR/20MnHR-B sample normalizing + simulated post-weld heat treatment:
Normalizing temperature: normalizing temperature 910℃±10℃, holding time 1.5min/mm, air cooling.
Simulated post-weld heat treatment process: holding temperature: 600℃±5℃, holding time: 10h.

20MnHR-BR/20MnHR-B steel mechanical properties:
Yield strength MPa ≥355
Tensile strength MPa510-640
Elongation%≥22
Shock temperature -20
Akv(J)≥40, vertical and horizontal: Akv≥21J