Hammer crusher is a widely used crushing machinery in cement, ceramics, mining, electric power, and other industries, the crusher hammers are its main wear parts, for a long time more high manganese steel manufacturing, when the impact on the crushed material is not strong, high manganese steel with work-hardening properties can not be fully played, so high manganese steel hammers show the weakness of fast wear, short service life. Practice shows that the anti-wear castings are anti-wear, in addition to the quality of the casting itself, but also with the casting service conditions have a close relationship with the specific working conditions.
According to the actual needs of customers, CH Casting has developed the following five materials:
- Low alloy steel
- Medium manganese cast steel
- High manganese steel
- High-carbon chromium-nickel-molybdenum alloy steel
- High chromium alloy steel
1. Low Alloy Steel
In all kinds of anti-wear parts, more than 80% are working under medium and low-stress impact wear conditions. Low-alloy steel can control the reasonable matching of hardness and toughness in a wide range because of its comprehensive performance of high hardness and sufficient toughness, and by adjusting the composition and heat treatment process. In recent years, a variety of low-alloy wear-resistant steels have been developed and applied to hammerheads to obtain martensite, austenite-bainite, and bainite-martensite matrix organization. The most widely used low-alloy martensitic steels are mainly alloyed with Cr, Ni, and Mo, and then quenched and tempered at low temperatures to obtain tempered martensite organization. Low-alloy martensitic wear-resistant steel has obvious superiority compared with austenitic high manganese steel under medium impact wear conditions, and the comprehensive mechanical properties are more than double that of high manganese steel, but the steel mainly relies on the hardness of the martensitic matrix to resist wear.
However, the steel mainly relies on the martensitic matrix hardness to resist wear, in the high-stress abrasive wear conditions, wear resistance is not much improved. The following table shows the composition and properties of several new low-alloy martensitic steel hammers:
| Table 1 Composition and properties of several new low-alloy martensitic steel hammers | |||||||||||
| Series | Material | Chemical Composition (%) | Mechanical properties | ||||||||
| C | Si | Cr | Mn | Ni | Mo | Other | HRC | Ak/J*cm-2 | MPa | ||
| 1 | ZG30Cr2MnMoSiVRE | 0.3 | 1.25 | 2.1 | 1 | 0.15-0.20 | 0.45 | 52-54 | 34.5 | 1712 | |
| 2 | ZG28Cr2MnMo | 0.28 | 0.2 | 2.1 | 0.69 | 0.15 | 0.51 | 33.1-41.5 | 1510 | ||
| 3 | ZG27Cr2SiMnREB | 0.25-0.30 | 1.4-1.6 | 1.5-2.0 | 0.8-1.2 | – | 0.3-0.5 | 50 | 68.2 | 1689 | |
| 4 | ZG30CrMnSi | 0.32-0.28 | 0.65-1.0 | 0.75 | 1.3 | ||||||
| 5 | ZG30CrMnSiMo | 0.28-0.38 | 0.7-0.9 | 1.2-1.6 | 1.2-1.4 | 0.2-0.4 | Re0.1,Ti0.1 | 45 | 140 | ||
| 6 | ZG35CrMn2SiMoB | 0.3-0.4 | 1.0-1.5 | 0.8-1.2 | 1.5-2.0 | 0.1-0.3 | B0.001-0.003 | 50 | |||
| 7 | ZG50Cr2MnSiMo | 0.45-0.53 | 0.8-1.0 | 2.0-3.0 | 1.0-1.4 | 0.15-0.25 | 53 | ||||
| 8 | ZG45Cr2MnSiMoNi | 0.48 | 0.8-1.0 | 2.0-2.5 | 1.0-1.4 | 0.2-0.3 | 0.2-0.4 | ||||
1.1 High silicon manganese medium carbon low alloy wear-resistant steel
This material chemical composition:
- C 0.43%
- Si 1.3%
- Mn 1.2%
- Cr 1.8%
- Mo 0.25%
- B small
- Re small
Its heat treatment process adopts an interrupted normalizing process:
Casting pouring temperature ≥ 1500 ℃, when cooled to about 900 ℃ hit the box, and then let it cool in the air to 300 ℃ -400 ℃, and then the casting into a constant heat container insulation for 10mins, and then placed in the cold air cooling to room temperature.
Its mechanical properties:
- Bainitic + martensitic duplex metallographic organization
- Bainite content is around 30%
- HRC 53
- αk 22.5J/cm²
This material crusher hammers test results:
- Excellent impact toughness and wear resistance
- 6.4 times working life than normal manganese steel crusher hammers
- 1.5 times working life than martensitic ductile casting Iron hammers
- Does not contain rare elements
- Heat treatment without secondary Heating
- Save a lot of energy and increase labor productivity
1.2 Boron-containing, high-strength, low-alloy martensitic + bainitic wear-resistant steel
This material chemical composition:
- C 0.3%-0.43%
- Si 0.8%-1.8%
- Mn 1.0%-1.8%
- Cr 0.8%-1.8%
- Mo 0.1%-0.5%
- Cu 0.1%-0.5%
- TI 0.001%-0.003%
- Re 0.02%-0.06%
Its heat treatment process:
- 880℃ * 30mins Quenching
- 250℃ * 1-hour Low-temperature tempering
- Quenching medium is oil
Its mechanical properties:
- The metallographic organization is Maraging mainly, with a considerable amount of bainite
- 1305-1780MPa
- HRC 45-57
- αk 76-150J/cm²
This material crusher hammers test results:
- Use under medium and low-stress abrasive wear conditions, its span life is around 1.5-3.5 times more than Mn13 crusher hammers.
1.3 Cast austenitic + bainitic wear-resistant steel
This material chemical composition:
- C 0.3%-0.5%
- Si 2.0%-3.2%
- Mn 1.5%-3.0%
- Cr 0.5%-1.5%
- Mo 0.1%-1.5%
- Little V, Ti, B, Re
Its mechanical properties:
- The metallographic organization is Maraging mainly, with a considerable amount of bainite
- HRC 40-58
- αk≥ 15-45J/cm²
This material crusher hammers test results:
- Excellent resistance to abrasive wear Performance
- 2 times span life than normal manganese steel hammers
- No heat treatment is required for use in cast state, simple and low-cost production process
1.4 Wear-resistant steel with controlled cooling to obtain bainite + martensite
Bainite, especially lower bainite, has excellent toughness and higher wear resistance than martensite at the same hardness. Controlled cooling is used to obtain bainitic + martensitic wear-resistant steels by inexpensive Si, Mn alloying. This material chemical composition:
- C 0.35%-0.7%
- Si 1.0%-2.5%
- Mn 2%-4%
- Little V, Ti, B, Re
Its heat treatment process:
- After austenitizing the casting at 900°C, holding time 1 hour
- Using jetting (large cooling speed) to make the workpiece in the cooling process, avoid the pearlite zone, rapid cooling to the bainite transformation zone, and termination of jetting cooling, the key to control cooling is to terminate the jetting operation at the right time, in order to achieve the appropriate termination temperature.
- The appropriate termination temperature is 260-350 ℃
- The use of appropriate insulation measures to create external conditions similar to isothermal quenching by using the residual heat of the casting to complete the bainite transformation.
Its mechanical properties:
- The organization after heat treatment is bainite, martensite and residual austenite, and the amount of residual austenite is about 7-11%.
- HRC ＞50
- αk≥ 20J/cm²
This material crusher hammers test results:
- Excellent resistance to abrasive wear Performance
- 1 times span life than normal manganese steel hammers
2. Medium manganese cast steel
2.1 High carbon medium manganese steel
High-carbon medium manganese steel is suitable for medium-impact load conditions, using the appropriate increase in carbon content to reduce the amount of manganese. This material chemical composition:
- C 1.58%-1.9%
- Si 0.28%-0.48%
- Mn 5.0%-6.5%
- Cr 1.0%-2.0%
Its heat treatment process:
- 1050 ℃ * 1 hour Water Hardening
- 350 ℃ * 4 hours Tempering
With appropriate chromium alloying and rare earth metamorphic treatment and other measures, you can get good toughness and high hardness, good wear resistance of the material. As the austenite stability of manganese steel is low, in a small impact stress is produced under the role of deformation martensite and process hardening, the wear resistance of manganese steel compared to high manganese steel increased by more than 40%.
2.2 Medium manganese steel
This material chemical composition:
- C 0.9%-1.1%
- Si 0.5%-0.8%
- Mn 6.0%-9.0%
- Cr 1.0%-1.2%
- other rare elements
Its mechanical properties:
- The cast metallographic organization of medium manganese steel is austenite + martensite + brittle-nite + carbide
- HB200-215
- αk≥ 50J/cm²
Due to the combined effect of solid solution strengthening of carbon, precipitation strengthening of carbide and deformation-induced martensite phase transformation, the medium manganese steel has good work-hardening properties. The life of cast medium manganese steel hammers is 60% higher than that of high manganese steel. Although the water-toughened medium manganese steel has good work-hardening effect, its hardness after hardening is only slightly higher than 500HV, and the hammer is easily cut by materials, so its life is slightly higher than that of high manganese steel. But because of its good work hardening effect and high toughness. It can be expected. It can be expected that the hammer can be used in applications where the impact is slightly larger. It is also possible to get good results.
3 High manganese steel
High manganese steel is still the traditional material of crusher hammers. After years of use, we found that the high manganese steel hammer head is not wear-resistant. Short service life. The crusher hammers for crushing limestone can generally work for 2-3 months. In some working conditions. Under some working conditions, they can be used for less than a week. The reason why high manganese steel hammer is not wear-resistant. As mentioned above. One is that the wear of the crusher hammer is mainly for scouring wear. The second is that the hammer crusher hammer in the operation process of the impact force is not large. So that the high manganese steel hammer hardening effect is not significant. Therefore. As the material of large crusher hammer. Reinforced high manganese steel is still the material of choice. Three new types of high manganese steel are introduced below.
3.1 Super high manganese steel
After heat treatment, part of the solid solution in austenite, part of the formation of dispersion carbide, so that its initial hardness and yield strength is greatly improved, while maintaining high toughness, in the steel, punching into rare earth elements, can purify the grain boundary inclusions, and further improve performance.
This material chemical composition:
- C 0.9-1.2%
- Si 0.4-0.6%
- Mn 14-18%
- Cr 2.0–3.0%
- Mo 0.5-1.0%
- V 0.15-0.25%
- TI 0.1-0.2%
- Re 0.2%
Its heat treatment process:
- Pre-treatment by normalizing. To homogenize the as-cast structure and refine the grains.
- Then the temperature is raised again at a specific rate, held, and quickly quenched.
- As the steel contains more alloying elements, the quenching temperature must be increased to extend the holding time, in order to make the alloying elements solid solution in the austenite, in order to make diffuse carbide precipitation in the crystal.
Its mechanical properties:
- HB 230-320
- 420-480 MPa
- αk≥ 100-150J/cm²
- Suitable for high-impact, high-stress, and harsh working conditions
- 2-3 times working life than normal manganese crusher hammers
3.2 High manganese alloy steel
This material chemical composition:
- C 0.9-1.3%
- Si 0.3-0.8%
- Mn 11-14%
- Cr 2.0–3.0%
- Mo 0.5-1.0%
- V 0.15-0.25%
- TI 0.1-0.2%
- Re 0.2%
Its mechanical properties:
- αk≥ 80-120J/cm²
- Elongation 15%-25%
- HB200-230
4 High-carbon chromium-nickel-molybdenum alloy steel
The use of higher carbon content, in order to obtain a high hardness matrix and a certain number of carbide hard phases, in order to resist hard material chiseling abrasive wear; and chromium, nickel, molybdenum and other alloying elements with the addition. Significantly improve its hardenability, so that the crusher hammer in air-cooled conditions can also be quenched into martensite. The addition of nickel to further improve the toughness of steel, titanium, rare earths can be added to refine the grain, purify the grain boundaries, improve the strength of steel.
This material chemical composition:
- C 0.65-1.1%
- Si 0.4-0.8%
- Mn 0.6-0.9%
- Cr 3.5-6.0%
- Mo 0.3-0.5%
- Ni 0.8-1.8%
Its mechanical properties:
- αk≥ 14-20J/cm²
- Hardness HRC 52-58
This material crusher hammers test results:
- Excellent resistance to abrasive wear Performance
- 2.8-4.7 times span life than normal manganese steel hammers
5 High chromium alloy steel
This material chemical composition:
- C 1.3-1.6%
- Si 0.1-0.5%
- Mn 0.3-0.5%
- Cr 11.0-14.0%
The metallographic organization is: martensite + eutectic carbide + a small amount of residual austenite + secondary carbide
This material crusher hammers test results:
- Lower toughness
- High abrasion resistance
- Suit for small crusher hammers
- Easy break
- 6-8 times than normal manganese steel
CH Casting is a professional crusher hammer manufacturer in China. We supply different materials for different working conditions. Such as the MA series for limestone; the DH series for metal recycling…If you have any inquiries or questions, please contact us freely!
