45HN, 40ChN, 40KhN - alloy structural steel for thermal improvement in accordance with PN-89/H-84030/04 and PN-72/H-84030.
| Standards | Steel Grades | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Chemical Composition % | |||||||||||||
| C: | Mn: | Si: | P: | S: | Cr: | Mo: | Ni: | V: | Ti: | Cu: | N: | W: | |
| PN | 45HN | ||||||||||||
| 0.41 - 0.49 | 0.5 - 0.8 | 0.17 - 0.37 | <0.035 | <0.035 | 0.45 - 0.75 | - | 1.0 - 1.4 | - | - | - | - | - | |
| GOST | 45ChN - 45KhN - 45ХН | ||||||||||||
| 0.41 - 0.49 | 0.5 - 0.8 | 0.17 - 0.37 | <0.035 | <0.035 | 0.45 - 0.75 | <0.15 | 1.0 - 1.4 | <0.05 | <0.03 | <0.30 | <0.008 | <0.2 | |
| GOST | 40ChN - 40KhN - 40ХН | ||||||||||||
| 0.36 - 0.44 | 0.5 - 0.8 | <0.20 | <0.035 | <0.035 | 0.45 - 0.75 | <0.15 | 1.0 - 1.4 | <0.05 | <0.03 | <0.30 | <0.008 | <0.2 | |
| GB/T | 45CrNi - A40452 - A 40452 | ||||||||||||
| 0.42 - 0.49 | 0.5 - 0.8 | 0.17 - 0.37 | <0.035 | <0.035 | 0.45 - 0.75 | <0.15 | 1.0 - 1.4 | - | - | <0.30 | - | - | |
| GOST | 40ChN-Sh - 40KhN-Sh - 40ХН-ш | ||||||||||||
| 0.36 - 0.44 | 0.5 - 0.8 | 0.17 - 0.37 | <0.025 | <0.015 | 0.45 - 0.75 | <0.15 | 1.0 - 1.4 | <0.05 | <0.03 | <0.25 | <0.008 | <0.2 | |
| JIS | SNC 236 - SNC 1 - SNC236 - SNC1 | ||||||||||||
| 0.32 - 0.40 | 0.5 - 0.8 | 0.15 - 0.35 | <0.030 | <0.030 | 0.50 - 0.90 | - | 1.0 - 1.5 | - | - | <0.30 | - | - | |
| БДС | 45ChN - 45KhN - 45ХН | ||||||||||||
| 0.41 - 0.49 | 0.5 - 0.8 | 0.17 - 0.37 | <0.035 | <0.035 | 0.45 - 0.75 | <0.15 | 1.0 - 1.4 | <0.05 | <0.03 | <0.30 | - | <0.2 | |
Steel 45HN - Specification and application
Structural alloy steel with medium hardenability for thermal improvement, surface hardening - flame and inductive hardening, high strength, ductility and impact and abrasion resistance.
Used for parts of machines, motors, and motor vehicles which, due to their dimensions, cannot be carburized. The soaking of products in a cyanide salt bath increases the resistance to abrasion. The 45HN grade is also suitable for surface hardening after thermal improvement.
In addition, it has an improved surface abrasion resistance which it acquires during heating in saline bath containing cyanide. Moreover, the good feature of the 45HN grade is the resistance to deformation during hardening.
45HN steel is hard to weld, and treatment in exceptional cases should be done after softening. Used as steel for machine shafts, pinion cogwheels, toothed rims, screws, forged and folded shafts, piston rods for steam engines, hammers and pumps.
Mechanical properties of the 45HN grade
| Mechanical properties | ||
|---|---|---|
| Tensile strength | Rm | > 1030 MPa |
| Yield point | Re | > 835 MPa |
| Notch toughness | KCU | > 56 J |
| Contraction | Z | > 45 % |
| Elongation | A | > 10 % |
| Density | ρ | ~7,83 kg/dm3 |
| Hardness in softened state | HB | < 207 HB |
| Properties | Dimensions | |||||
|---|---|---|---|---|---|---|
| <16mm | 16 - 40mm | 40 - 100mm | 100 - 160mm | |||
| Tensile strength | Rm | 1080 - 1230 MPa | 980 - 1130 MPa | 830 - 980 MPa | 740 - 880 MPa | |
| Yield point | Re | > 880 MPa | > 780 MPa | > 690 MPa | > 540 MPa | |
| Notch toughness | KCU | - | > 40 J | > 40 J | - | |
| Contraction | Z | > 40 % | > 45 % | > 45 % | > 45 % | |
| Elongation | A | > 9 % | > 10 % | > 12 % | > 13 % | |
Heat treatment of 45HN steel
- For large dimensions 45HN steel is hardened in oil
- Tempering in 45HN water is done in water to avoid temper brittleness
| Heat treatment type | Cooling type | Temperatures |
|---|---|---|
| Normalizing annealing | in calm air | 840 - 880℃ |
| Softening annealing | slow cooling | 680 - 720℃ |
| Hardening | in water | 810 - 840℃ |
| w oleju | 820 - 850℃ | |
| Tempering | in water | 550 - 650℃ |
| in air | 550 - 650℃ |
Welding, joining and cutting of 45HN steel
45HN steel products can be arc plasma, oxyacetylene, and propane-butane oxygen cut. Before cutting steel needs to be heated to 250 - 300 ℃. After cutting, the steel should be cooled in the air.
45HN can be frictionally, resistively or electrically welded in a softened and heat-treated state, making after the process a suitable heat treatment to maintain stable material parameters.
As mentioned above, 45HN steel does not belong to easily weldable grades. The treatment should be performed only in exceptional circumstances in the softened state of delivery of the material. Steel with a much larger dimensions requires interoperable relacing annealing.
Steel can be arc-welded with coated electrodes or in CO 2 casing with pre-heating of the material to appropriate temperatures. When the welding procedure is completed before the material has cooled down, the joints should be subjected to softening annealing.
If the conditions do not allow for treatment, the steel should be covered with mats or cooled in the hot sand.
Below the temperature table for preheating the material before welding.
| Temperatures of soaking of 45HN material | |||
|---|---|---|---|
| Dimensions | < 15mm | 15 - 25mm | 25 - 50mm |
| Temperatures | 150 - 250℃ | 200 - 300℃ | 250 - 350℃ |
In the 45HN grade the company delivers:
List of equivalents and other determinations of 45HN steel:
45ChN, 45KhN, 45ХН, 40ChN, 40KhN, 40ХН, 45CrNi, A40452, A 40452, 40ChN-Sh, 40KhN-Sh, 40ХН-ш, SNC 236, SNC 1, SNC236, SNC1, 45ChN, 45KhN, 45ХН