37HS - Chromium-silicon alloy structural steel for construction of heavy-duty and load-bearing parts for thermal improvement in accordance with PN-72 / H-84030.
| Standard | Steel Grades | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Chemical Composition % | |||||||||||||
| C: | Mn: | Si: | P: | S: | Cr: | Mo: | Ni: | V: | Ti: | Cu: | W: | N: | |
| PN | 37HS | ||||||||||||
| 0.34 - 0.42 | 0.3 - 0.6 | 1.0 - 1.4 | <0.035 | <0.035 | 1.3 - 1.6 | - | <0.3 | - | - | - | - | - | |
| GOST | 38HS - 38ChS - 38KhS - 38ХС | ||||||||||||
| 0.34 - 0.42 | 0.3 - 0.6 | 1.0 - 1.4 | <0.035 | <0.035 | 1.3 - 1.6 | <0.15 | <0.3 | <0.05 | <0.03 | <0.30 | <0.2 | <0.008 | |
| БДС | 38ChS | ||||||||||||
| 0.34 - 0.42 | 0.3 - 0.6 | 1.0 - 1.4 | <0.035 | <0.035 | 1.3 - 1.6 | <0.15 | <0.3 | <0.05 | <0.03 | <0.30 | <0.2 | - | |
| ČSN STN | ČSN 14 341 - ČSN 14341 | ||||||||||||
| 0.34 - 0.42 | 0.3 - 0.6 | 1.0 - 1.3 | <0.035 | <0.035 | 1.3 - 1.6 | - | - | - | - | - | - | - | |
| GOST | 38ChS-Sh - 38KhS-Sh - 38ХС-ш | ||||||||||||
| 0.34 - 0.42 | 0.3 - 0.6 | 1.0 - 1.4 | <0.025 | <0.015 | 1.3 - 1.6 | <0.15 | <0.3 | <0.05 | <0.03 | <0.25 | <0.2 | <0.008 | |
| GB/T | 38CrSi - A21382 - A 21382 | ||||||||||||
| 0.35 - 0.43 | 0.3 - 0.6 | 1.0 - 1.3 | <0.035 | <0.035 | 1.3 - 1.6 | <0.15 | <0.3 | - | - | <0.30 | - | - | |
Steel 37HS - specification and application
Enhanced hardening steel for heat improvement demonstrating its properties after hardening in oil and tempering. It is abrasion-resistant, suitable for large and variable loads. For heavy-duty, high wear and torsion resistant parts, medium-sized heavy duty machines such as friction discs, cams, clutch discs, gears, camshafts, studs, axles, screws and even suction valves
Also used in medium-sized cars, excavators or tractors. 37HS steel is difficult to weld.
37HS also features spring steel properties with low tempering - high strength, wear resistance, elasticity and plasticity.
Mechanical and physical properties
- Tensile strength Rm ≥ 930 MPa
- Yield point KU2 ≥ 56 J
- Elongation A ≥ 12%
- Contraction Z ≥ 50%
- Density ρ = 7.74 - 7.85 kg/dm3
- Electrical resistance at 20℃, ρ = 0.20 ⋅ 10-4 Ω ⋅ cm
- Specific heat (capacity) at 20℃, cp = 0.11 cal/(g ⋅ ℃)
- Hardness in a softened state, HB = max. 255
- Hardness after drawing in the softened state, HB = max. 255
- Hardness after drawing in the hardened state, HB = max. 293
| Property | Dimensions and values | |||||
|---|---|---|---|---|---|---|
| 16 - 40mm | 40 - 100mm | 100 - 160mm | 160 - 250mm | |||
| Tensile strength | Rm | ≥ 930 MPa | ≥ 830 MPa | ≥ 740 MPa | ≥ 740 MPa | |
| Notch toughness | KU2 | ≥ 30 J | ≥ 30 J | ≥ 30 J | ≥ 30 J | |
| Yield point | Re | ≥ 740 MPa | ≥ 640 MPa | ≥ 540 MPa | ≥ 540 MPa | |
| Contraction | Z | ≥ 50% | ≥ 55% | ≥ 60% | ≥ 60% | |
| Elongation | A | ≥ 12% | ≥ 14% | ≥ 15% | ≥ 15% | |
Thermal treatment
| Heat treatment - process and temperatures | ||
|---|---|---|
| Normalizing annealing | cooling in calm air | 900 - 930℃ |
| Softening annealing | slow cooling | 680 - 720℃ |
| Hardening | in oil | 880 - 990℃ |
| Odpuszczanie | in oil or water | 530 - 670℃ |
| Tempering for elastic properties | 250 - 280℃ | |
Longitudinal modulus of elasticityE
| Longitudinal modulus of elasticityE ⋅ 10-3 | ||||
|---|---|---|---|---|
| 20℃ | 100℃ | 200℃ | 300℃ | 400℃ |
| 21.0 kG/mm2 | 19.5 kG/mm2 | 18.5 kG/mm2 | - | 17.5 kG/mm2 |
Welding, joining and cutting of 37HS steel
Semi-finished products mode of 37HS grade steel before cutting should be preheated to 250 - 300℃. The steel can be cut with propane-butane-oxygen torch, oxyacetylene blowpipe, or plasma torch. After the treatment the product should be cooled in calm air.
37HS can also be joined in an softened annealed condition or heat treated - resistance welding, friction welding or electric welding. However, be sure to select the optimum parameters in narrower ranges than the parameters for low carbon steels.
37HS is not easy to weld, therefore welding should be avoided and should be used in exceptional cases in a softened state. As with cutting, steel should be heated to a suitable temperature depending on the dimensions of the product. 37HS steel is arc-welded with electrodes - ES1.76, ES1.55, ES1.50, ES18-8-6 or CO2 welding - SP1GS.
Steel is recommended to be welded in a softened state. In the case of welding of heat-treated parts, the area around the jointing sites will have worse endurance properties than in the welded locations, so it should be welded immediately before the material has cooled below the heating temperature, the material at the joints is to be heat-treated or annealed.
In the absence of heat treatment, the steel should be cooled with asbestos-based mats, cooled in hot sand when removed from the furnace, or slowly cool the furnace together with the steel. Prior to welding large products or larger sections, it is recommended to carry out interoperative relaxing annealing.
| 37HS heating temperatures before welding | ||
|---|---|---|
| dimensions | temperature | |
| ≤ 15mm | 150 - 250℃ | |
| 15 - 25mm | 200 - 300℃ | |
| ≥ 25mm | 250 - 350℃ | |
In the 37HS grade the company provides:
List of equivalents and other determinations of 37HS steel:
38HS, 38ChS, 38KhS, 38ХС, ČSN 14 341, ČSN 14341, 38ChS-Sh, 38KhS-Sh, 38ХС-ш, 38CrSi, A21382, A 21382