Abstract:
This article comprehensively reviews the characteristics, classifications, and current application status of wear-resistant steel castings. It introduces typical wear-resistant steel castings and their production processes, elaborates on the main standards for wear-resistant steel castings, and discusses their development trends. By exploring the technical field and analyzing development trends, this article aims to provide beneficial insights and suggestions for the future development of the wear-resistant materials industry in China.
Keywords: Wear-resistant steel; Wear-resistant steel casting; Standards
I. Introduction
The wear-resistant steel material industry in China is renowned worldwide for its vast production scale and diverse product range. From austenitic wear-resistant manganese steel, wear-resistant white cast iron, non-manganese wear-resistant alloy steel, wear-resistant ductile iron to wear-resistant iron-based composites, China boasts a wide variety of wear-resistant materials that cater to the needs of numerous industrial sectors such as metallurgy, building materials, electricity, construction, machinery, national defense, shipping, railways, coal, chemicals, and petrochemicals. Statistics indicate that China annually requires approximately 5 million tons of wear-resistant steel castings.
Wear-resistant steel castings are a major category within wear-resistant castings, commonly used in large-scale heavy industrial production due to their excellent wear resistance and strong toughness. This article, combined with national standards for wear-resistant steel castings and recent advancements in domestic wear-resistant steel casting technology, focuses on the development and innovation of industrialization technologies to introduce wear-resistant steel castings and their development trends.
II. Classification of Wear-resistant Steel
Table 1: Classification of Wear-resistant Steel
| Category | Sub-category | Main Characteristics |
|---|---|---|
| Cast Wear-resistant Manganese Steel | High Manganese Steel (Mn13 Series) | High surface hardness after work hardening, good plasticity and toughness in the interior |
| Medium Manganese Steel (Mn7) | Higher wear resistance than standard Mn13 under non-severe impact conditions | |
| Ultra-high Manganese Steel (Mn18 Series) | Higher service life under high-impact abrasive wear conditions | |
| Non-manganese Wear-resistant Alloy Steel | Medium-carbon Low-alloy Steel | High strength, hardness, and toughness; suitable for non-heavy impact wear conditions |
| Medium-carbon Medium-alloy Steel | Better combination of hardness and toughness | |
| Low-carbon High-alloy Steel | Developed for wet ball mill liners in metallurgical mines |
1. Cast Wear-resistant Manganese Steel
- High Manganese Steel (Mn13 Series)
- Invented by R.A. Hadfield in 1882, high manganese steel is characterized by its high surface hardening degree and retained high toughness in the core. It exhibits superior wear resistance compared to other materials under large pressure and impact.
- The main composition remains relatively unchanged, with carbon content ranging from 0.7% to 1.4% and manganese content from 10% to 14%.
- Carbon plays two roles: facilitating the formation of a single-phase austenitic structure and providing solid solution strengthening.
- Manganese stabilizes the austenitic structure. When the manganese-to-carbon mass ratio (Mn/C) is around 10, high manganese steel achieves a good combination of strength and toughness.
- Medium Manganese Steel (Mn7)
- Contains 1.05% to 1.40% carbon and 5% to 9% manganese. After water toughening treatment, its structure is austenitic, but with more carbides.
- Lower manganese content reduces austenitic stability, resulting in higher wear resistance than standard Mn13 under non-severe impact conditions.
- Ultra-high Manganese Steel (Mn18 Series)
- Addressed issues of Mn13 series steel, such as carbide precipitation in thick sections after water toughening and brittleness at low temperatures.
- Increases in manganese content enhance austenitic stability, prevent carbide precipitation, and improve strength, plasticity, and work hardening ability.
2. Non-manganese Wear-resistant Alloy Steel
- Known for their high hardness, toughness, and strength, particularly with a good match between hardness and toughness.
- Mainly divided into medium-carbon low-alloy steel, medium-carbon medium-alloy steel, and recently developed low-carbon high-alloy steel.
III. Typical Castings and Production Processes
Table 2: Typical Wear-resistant Steel Castings and Their Production Processes
| Casting Type | Material | Production Process | Application |
|---|---|---|---|
| High Manganese Steel Wear-resistant Casting | Mn13, Mn18, etc. | Melting, Pouring, Water Toughening Treatment | Ball mill liners, hammer crusher hammerheads, jaw crusher jaw plates |
| Alloy Steel Wear-resistant Casting | Low-alloy, medium-alloy, high-alloy steel | Melting, Pouring, Heat Treatment (Water Quenching, Oil Quenching, Air Quenching + Low-temperature Tempering) | Ball mill liners, jaw plates, hammerheads, wear-resistant pipelines |
1. Casting Process for High Manganese Steel Wear-resistant Castings
- Melting: Uses an induction furnace or electric arc furnace.
- Pouring: Requires strict control of pouring temperature and pouring speed to avoid defects.
- Water Toughening Treatment: Critical step to obtain a single-phase austenitic structure, improving plasticity and toughness.
2. Casting Process for Alloy Steel Wear-resistant Castings
- Melting and Pouring: Similar to high manganese steel but with additional alloying elements.
- Heat Treatment: Depending on the alloy composition, can involve water quenching, oil quenching, or air quenching followed by low-temperature tempering to obtain desired mechanical properties.
IV. Standards for Wear-resistant Steel
Table 3: Standards for Wear-resistant Steel Castings
| Standard Name | Main Content |
|---|---|
| Austenitic Manganese Steel National Standard | Specifies chemical composition, mechanical properties, and testing methods for austenitic manganese steel castings, including Mn13, Mn18, and Mn25. |
| Non-manganese Wear-resistant Alloy Steel National Standard | Defines 11 typical grades of non-manganese wear-resistant alloy steel castings, specifying chemical composition, heat treatment processes, mechanical properties, and hardness requirements. |
1. Austenitic Manganese Steel National Standard
- Focuses on controlling Si and P content to improve performance.
– V, Ti, Nb, and RE are often added to reduce inclusions, columnar crystals, and coarse grains. - Ultra-high manganese steels like Mn18 and Mn25 have been produced and applied, but further research is needed to validate their wear resistance and cost-effectiveness under various conditions.
2. Non-manganese Wear-resistant Alloy Steel National Standard
- Specifies chemical composition, including C, Si, Mn, Cr, Mo, and Ni, to ensure necessary strength, hardness, toughness, and hardenability.
- Allows the addition of trace elements V, Ti, Nb, B, and RE to refine grain size and improve mechanical and wear properties.
- Defines heat treatment processes and mechanical property requirements, including hardness and impact absorption energy.
V. Conclusion
In recent years, advancements in austenitic manganese steel have focused on strictly controlling Si and P content, particularly limiting phosphorus to ≤0.04% for some export products. The addition of trace elements like V, Ti, Nb, and RE has been employed to reduce inclusions, columnar crystals, and coarse grains. Ultra-high manganese steels such as Mn18 and Mn25 have been produced and applied, but further research is required to validate their wear resistance and cost-effectiveness under high-impact abrasive wear conditions.
For non-manganese wear-resistant alloy steels, particularly medium-carbon low- and medium-alloy steels, the development direction is to improve the combination of strength, hardness, and toughness to enhance overall resistance to impact and wear.
With the rapid development of heavy machinery in China and increasingly demanding working environments, the demand for wear-resistant materials in the engineering field is growing. Therefore, in future developments, we need to further strengthen technological innovation, continuously improve product quality, and reduce production costs to meet market demands. It is believed that with continuous efforts and development, China’s wear-resistant materials industry will usher in a brighter future and contribute more to the development of the engineering field.