30HGSA, 30HGS structural alloy steel for thermal improvement, heavy-duty constructions and construction of parts of heavy-duty machines - aviation steel according to PN-89/H-84030/04.
| Standards | Steel Grades | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Chemical Composition % | |||||||||||||
| C: | Mn: | Si: | P: | S: | Cr: | Mo: | Ni: | V: | Ti: | Cu: | N: | W: | |
| PN | 30HGSA | ||||||||||||
| 0.28 - 0.34 | 0.8 - 1.1 | 0.9 - 1.2 | <0.025 | <0.025 | 0.8 - 1.1 | - | <0.3 | - | - | - | - | - | |
| PN | 30HGS | ||||||||||||
| 0.28 - 0.35 | 0.8 - 1.1 | 0.9 - 1.2 | <0.035 | <0.035 | 0.8 - 1.1 | - | <0.3 | - | - | - | - | - | |
| GOST | 30ChGSA - 30KhGSA - 30ХГСА | ||||||||||||
| 0.28 - 0.34 | 0.8 - 1.1 | 0.9 - 1.2 | <0.025 | <0.025 | 0.8 - 1.1 | <0.15 | <0.3 | <0.05 | <0.03 | <0.30 | <0.008 | <0.2 | |
| ČSN/STN | ČSN 14 331 - ČSN 14331 - ČSN 414331 | ||||||||||||
| 0.28 - 0.35 | 0.8 - 1.1 | 0.9 - 1.2 | <0.035 | <0.035 | 0.8 - 1.1 | - | - | - | - | - | - | - | |
| GOST | 30ChGSA-sh - 30KhGSA-sh - 30ХГСА-ш | ||||||||||||
| 0.28 - 0.34 | 0.8 - 1.1 | 0.9 - 1.2 | <0.025 | <0.015 | 0.8 - 1.1 | <0.15 | <0.3 | <0.05 | <0.03 | <0.25 | <0.008 | <0.2 | |
| PN | 25HGS | ||||||||||||
| 0.22 - 0.28 | 0.8 - 1.1 | 0.9 - 1.2 | <0.035 | <0.035 | 0.8 - 1.1 | - | <0.3 | - | - | - | - | - | |
| GOST | 25ChGSA - 25KhGSA - 25ХГСА | ||||||||||||
| 0.22 - 0.28 | 0.8 - 1.1 | 0.9 - 1.2 | <0.025 | <0.025 | 0.8 - 1.1 | <0.15 | <0.3 | <0.05 | <0.03 | <0.30 | <0.008 | <0.2 | |
| GB/T | 30CrMnSiA - A24303 - A 24303 | ||||||||||||
| 0.28 - 0.34 | 0.8 - 1.1 | 0.9 - 1.2 | <0.025 | <0.025 | 0.8 - 1.1 | - | <0.3 | - | - | - | - | - | |
Steel for air constructions and air pipes, chromium-manganese-silicon
Highly hardenable steel, high wear resistance and durability, designed for heavy-duty machines construction. Also used on riveted parts, for part with medium dimensions, which work up to a maximum temperature of 150 - 200 ℃. Typically used for elements up to 60mm, due to the preservation of suitable mechanical properties. The relevant parameters only appear after thermal treatment.
The 30HGSA grade from the 30HGS steel differs withmore restrictive S-sulfur and P-phosphorus approvals in the chemical composition. This improves the properties and quality of the product.
The 30HGSA steel grade is used for products such as spindles, sprockets, levers, clutch parts, gears, flanges and bushings, heavy duty steel axles, shafts, and steel for compressor blades and airplane tubes.
Gerneral mechanical properties of 30HGSA
- Tensile strength Rm > 1080 MPa
- Yield point Re > 830 MPa
- Impact value KU2 > 36 J
- Elongation A > 10 %
- Reduction of area Z > 45 %
- Hardness in annealed cond. < 229 HB
- Hardness in the heat-treated cond. 295 - 360 HB
Mechanical properties for individual dimensions
| Properties | Dimensions | ||||
|---|---|---|---|---|---|
| < 16mm | 16 - 40mm | 40 - 100mm | 100 - 160mm | 160 - 250mm | |
| Tensile strength Rm (MPa) | 1030 - 1180 | 930 - 1080 | 830 - 980 | 690 - 880 | 690 - 830 |
| Yield point Re (MPa) | 830 - 930 | 740 - 830 | 590 - 690 | 490 - 590 | 490 - 590 |
| Elongation A (%) | 10 - 13 | 10 - 13 | 11 - 15 | 12 - 16 | 13 - 17 |
| Impact resistance KM (J/cm2) | 49 - 69 | 49- 69 | 49 - 69 | - | - |
Mechanical properties of bars in 30ChGSA acc. to GOST 4543-71
- Tensile Strenght Rm > 1620 MPa
- Yield point Re > 1275 MPa
- Impact value KCU > 39 J
- Elongation A > 9 %
- Reduction of area Z > 40 %
Mechanical properties of sheets and plates 30HGSA - GOST 11269
- Tensile strenght Rm > 1080 MPa
- Impact test KCU > 49 J
- Elongation A > 9 %
Seamless Tubes properties in 30HGSA - GOST 21729, GOST 8733, GOST 8731
- Tensile strenght Rm > 491 MPa
- Impact test KCU > 36 J
- Elongation A > 18 %
- Hardness HRB <98
Wire properties in 30HGSA - TU 14-4-385-73
- Tensile Strenght Rm:> 490-735 MPa
Welding of 30HGSA-30HGS steel
30HGSA steel products are difficult to weld. Avoid welding and or welded by arc welding, electric welding or CO2 welding in softened state. In the case of welding of an already-improved product, the place of welding and its area under heating will lose some of their properties.
It is therefore necessary to perform additional heat treatment after welding to restore the previous parameters. With larger components, it is recommended to have an relaxing annealing before the welding is completed, and after the welding is completed, slow cooling in hot sand, or asbestos-coated mats. Welding of 30HGSA steel requires preheating to a suitable temperature depending on the dimensions of the element.
Temperatures of preheating of components prior to welding should be:
- 200-300℃ for products up to 15mm
- 250-350℃ for products in the range of 15-25mm
- 350℃or more for products in the range of 25-50mm
Semi-finished products of 30HGSA steel are hard to weld. The procedure should be avoided or welded by arc welding, CO2 welding, or electric welding in an annealed state. In the case of welding of already heat-treated products, places close to welding point will partially lose their properties.
It is therefore necessary to perform additional heat treatment after welding to restore the previous parameters. With larger components, it is recommended to have an relaxing annealing before the welding is completed, and after the welding is completed, slow cooling in hot sand or asbestos-coated mats.
Prior to welding 30HGSA steel, preheat the product to a suitable temperature, depending on the dimensions of the product.
| Heating temperature depending on product dimensions | |
|---|---|
| Product dimensions | Temperature |
| > 15mm | 200 - 300℃ |
| 15 - 25mm | 250 - 350℃ |
| 25 - 50mm | > 350℃ |
Welding and cutting
Cutting of bars, 30HGSA pipes, sheets and other product should be made after preheating the material to a temperature range of 200-250 ℃. Materials can be cut with propane-butane-oxygen flame, oxyacetylene blowpipe, plasma torch, or machanically. The cut pieces should be cooled in the air.
An alternative to welding 30HGSA steel is friction welding, resistance welding or electric welding. Elements can be welded in an annealed softened or heat-treated without forgetting about proper heat treatment after finishing to maintain stable material properties.
Heat-treatment of products made of 30HGSA steel
In softened state, 30HGSA steel achieves hardness below ≤ 229 HB. In order to achieve the best performance, you should temper the steel in oil. Steel is prone to be fragile after tempering, so heat treatment should be carried out very carefully. After tempering in oil, products should be cooled to avoid the fragility of tempering. Hardening treatment is carried out at 860 - 900℃. After correct heat treatment hardness varies between 295 - 360 HB. Products with a smooth or light surface according to PN-H-93014, the hardness of bars after drawing is within the following limits:
- in the softened state < 229 HB
- in the hardened state < 277 HB
Other thermal processes:
- normalizing at 870-890 °C - cooling in oil or in calm air
- softening at 680-720 °C - cooling in oil or slow cooling
- Hardening at 860 - 880 ℃ with oil cooling
- tempering at temperature range 500-650 °C with cooling in oil
In the 30HGSA grade for thermal improvement, the company provides:
- Seamless hot-rolled and precision, colddrawn tubes 30HGSA
- Forgings, shafts and forged bars 30HGSA
- Hot-rolled and coldrolled sheets / bands 30HGSA
- Round hot-rolled bars, square and flat bars
- Cubes and plates
List of equivalents and other determinations of 30HGSA steel:
30 HGSA, ČSN 414331, 30HGS, 30ChGS, 30KhGS, 30ХГС, 30ChGSA, 30KhGSA, 30ХГСА, 30ChGSA-sh, 30HGSA, 25ChGSA, 30KhGSA-sh, 30CrMnSiA, 30ХГСА-ш, ČSN 14 331, 25HGS, 25XГCА, 25KhGSA, A24303, A 24303