AWS ER70S-B2L or ER49S-B2L (K20500) Weld Metal
AWS ER70S-B2L is a weld metal formulated for joining alloy steels. Cited properties are appropriate for the post-weld heat treated (PWHT) condition. ER70S-B2L is the AWS designation for this material. K20500 is the UNS number.
It has a moderately low embodied energy among alloy steel welding fillers. In addition, it has a fairly low tensile strength and a moderately low base cost.
The graph bars on the material properties cards below compare AWS ER70S-B2L to: alloy steel welding fillers (top), all iron alloys (middle), and the entire database (bottom). A full bar means this is the highest value in the relevant set. A half-full bar means it's 50% of the highest, and so on.
Mechanical Properties
Elastic (Young's, Tensile) Modulus
190 GPa 27 x 106 psi
Elongation at Break
22 %
Poisson's Ratio
0.29
Shear Modulus
73 GPa 11 x 106 psi
Tensile Strength: Ultimate (UTS)
590 MPa 85 x 103 psi
Tensile Strength: Yield (Proof)
450 MPa 65 x 103 psi
Thermal Properties
Latent Heat of Fusion
260 J/g
Melting Completion (Liquidus)
1460 °C 2660 °F
Melting Onset (Solidus)
1420 °C 2580 °F
Specific Heat Capacity
470 J/kg-K 0.11 BTU/lb-°F
Thermal Conductivity
40 W/m-K 23 BTU/h-ft-°F
Thermal Expansion
13 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
7.5 % IACS
Electrical Conductivity: Equal Weight (Specific)
8.6 % IACS
Otherwise Unclassified Properties
Base Metal Price
3.0 % relative
Density
7.8 g/cm3 490 lb/ft3
Embodied Carbon
1.6 kg CO2/kg material
Embodied Energy
21 MJ/kg 9.1 x 103 BTU/lb
Embodied Water
54 L/kg 6.4 gal/lb
Common Calculations
PREN (Pitting Resistance)
3.1
Resilience: Ultimate (Unit Rupture Work)
120 MJ/m3
Resilience: Unit (Modulus of Resilience)
530 kJ/m3
Stiffness to Weight: Axial
13 points
Stiffness to Weight: Bending
24 points
Strength to Weight: Axial
21 points
Strength to Weight: Bending
20 points
Thermal Diffusivity
11 mm2/s
Thermal Shock Resistance
17 points
Alloy Composition
| Fe | 95.3 to 97.6 | |
| Cr | 1.2 to 1.5 | |
| Mn | 0.4 to 0.7 | |
| Si | 0.4 to 0.7 | |
| Mo | 0.4 to 0.65 | |
| Cu | 0 to 0.35 | |
| Ni | 0 to 0.2 | |
| C | 0 to 0.050 | |
| P | 0 to 0.025 | |
| S | 0 to 0.025 | |
| res. | 0 to 0.5 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
AWS A5.28: Specification for Low-Alloy Steel Electrodes and Rods for Gas Shielded Arc Welding
Welding Metallurgy, 2nd ed., Sindo Kou, 2003