20Cr1Mo1VNbTiB China's self-developed low alloy high strength steel, also [SCALE STEEL]known as Zhengqi No.1 steel.
GB/T 20410-2006 "high temperature bolts for turbine steel"
DL/T 439-2018 "Technical guidelines for high-temperature fasteners in thermal power plants"
DL/T 715-2015 "Guidelines for Selection [SCALE STEEL]of Metal Materials in Thermal Power Plants"
Chemical Composition（%）（GB/T 20410-2006）
C 0.17~0.23 Cr 0.90~1.30
Si 0.40~0.60 Mo 0.75~1.00
Mn 0.40~0.65 V 0.50~0.70
P ≤0.025 Nb 0.11~0.22
S ≤0.025 Ti 0.05~0.14
Ni ≤0.30[SCALE STEEL] B 0.001~0.004
1020~1040℃ Oil Cooling，700~720℃ Tempering for 6h and then air cooling.
Mechanical Property（GB/T 20410-2006）
Sample Size（mm） Ø25
Heat Treatment Quenched（Oil,Water Cooling/℃ 1020~1040
Tempered（Air Cooling）/℃ 690~730
Mechanical Property TS Rm/MPa[SCALE STEEL] ≥785
YS Rp0.2/MPa ≥670
Hardness HBW 10/3000 255~305
1.Good high temperature performance, high durable strength and plasticity, good anti-relaxation performance, small thermal brittle tendency, low notch sensitivity.
2.Heat treatment is more [SCALE STEEL]sensitive, such as improper thermal processing control, easy to appear naked eye coarse grain, so there are strict grain size acceptance standards for different design grades.
The highest operating temperature is 570℃.
20Cr1Mo1VNbTiB bainite [SCALE STEEL]heat resistant steel has excellent comprehensive properties and is mainly used as high temperature bolts in thermal power plants below 570℃. It is widely used in large and medium-sized units in thermal power plants.