5 Things to Know Before Buying 1.2312 steel

Understanding the components of 1. materials is crucial. This alloy consists primarily of elements such as carbon, silicon, manganese, tungsten, molybdenum, chromium, and vanadium. As a chromium-nickel-molybdenum tool steel, its high chromium and nickel content enhances the hardness and corrosion resistance of 1. steel. Additionally, a small quantity of molybdenum provides improved strength and toughness. It's important to manage the ratio and concentration of these chemical elements since an excessive amount of silicon can lead to increased brittleness and a greater likelihood of cracking.

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Recent technological advancements have introduced a distinct pre-hardening production process for 1. steel, allowing it to achieve hardness levels exceeding 28HRC. Its optimal machinability is found at 40HRC, enabling efficient usage for advanced grinding purposes, while post-heat treatment can elevate hardness to 50.7HRC.

Applications of 1. Steel

(1) Mold Industry:
This steel can withstand prolonged exposure to high temperatures and pressure, exhibiting impressive corrosion resistance, thereby extending the mold's lifespan. It's an excellent choice for various molds, including those for plastics, die-casting, metals, and injections.

(2) Automotive Sector:
In the automotive realm, many components require high strength, hardness, and wear resistance for optimal vehicle safety and stability. 1. steel possesses these desirable traits and is vital in manufacturing key auto parts like bumpers, engine blocks, gears, chassis, and clutch discs.

Dongguan Songshun Mould Steel Co., LTD has established itself as a reputable industrial trading company equipped with hydraulic forging machines. We offer a wide range of steels, competitively priced without compromising quality, backed by extensive stock availability.

P20 is a modified alloy that has dominated the pre-hardened mold steel market for years. Classified as a chrome-moly alloy, it contains approximately 0.30 to 0.40 carbon. The market has seen various modifications to the basic P20 chemistry, each impacting specific molding fabrication processes.

Material Types

The U.S. mold-making industry has deep European roots, with immigrants bringing trade knowledge that greatly influenced mold construction. They often preferred chrome-moly steels such as DIN 1. and 1., closely related to AISI P20.

Globally, P20 varies from region to region. The Europeans tend to use DIN specifications (1. and 1.), while the Japanese market has adopted PX5 as the standard P20. In China, however, uncertainty surrounds the materials used in their molds, complicating matters for secondary processing concerning polishing and texturing.

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The U.S. market is a melting pot of different grades.

As illustrated in Figure 1, there exists a chemical breakdown of materials in the U.S., showcasing the variances within the P20 family. Depending on the supplier, an order of P20 could comprise any one of the variations available. Some entries listed, like P20 premium and high hard P20, are chemically closer to steel materials like chrome-nickel-moly. P20 falls within the chrome-moly family.

Variations between suppliers can impact costs and processing times. Moldmakers typically assess key factors like machinability and stability when opting for P20. If the steel's chemistry leads to hard spots (carbide segregation), machining becomes more challenging, significantly increasing costs. Machining can represent over half of mold-building expenses, hence any delay in machining time proves costly. Hard spots also decrease the life of cutters and inserts, further driving up costs. If the chemistry does not minimize hardness disparities between the surface and the core, it will induce more stress in the steel, leading to warping during machining, requiring thermal stress-relieving, thus adding to costs and lengthening lead times.

Surface Finish Quality

Upon leaving a mold shop, a specific surface finish is often requested—polishing, texturing, or EDM finishing. The quality of the utilized P20 critically impacts these processes. Four primary factors affect the surface finish quality:

1. Content Percentage: The elements mixed into the steel directly influence its ability to polish and texture. For instance, sulfur content plays a role in the polishing process. Higher sulfur levels make achieving a mirror finish more difficult, leading to pitting on the surface. Most P20 steels achieve a decent #2 finish, while #3 steel, with minimal sulfur, offers superior polishability, albeit at the expense of machinability.
2. Uniformity of Alloy Distribution: The elements combined with iron must be evenly distributed in the steel matrix. Uneven distribution may result in imperfections such as voids, hard spots, or soft spots, increasing costs for corrections.
3. Hardness Consistency: P20 is commonly textured through an acid etching process. If hardness is inconsistent, surface texture depth will vary, which is problematic for large P20 blocks due to differing hardness between the surface and the core.
4. Welding Considerations: Texturing P20 involves risks around welds within the mold. The heat-affected zone (HAZ) around welds can exhibit hardness levels that exceed the base metal by 15 or more HRC points. With a base hardness of 28-32 HRC, the hardness differential can yield texture depth variations of up to 60%. This discrepancy creates a halo effect on textures, requiring additional handwork and resulting in increased lead times and costs.

The alloy content significantly affects the welding process as well. Higher alloy content increases the risk of cracking. Many high-quality P20 versions, especially those from Japan, feature lower carbon content and, in turn, higher toughness, making cracking relatively rare. The lower carbon level minimizes hardness increases in the HAZ. Conversely, higher carbon and alloy contents in standard P20s or some high-hard variants necessitate careful heating protocols to mitigate cracking and extreme hardening, adding both time and cost to the welding process.

Making Your Choice

Steel manufacturers globally, particularly in the U.S., Europe, and Japan, are under pressure to innovate enhanced grades of mold steels. Advanced melting techniques, refined materials, and additives are becoming accessible for moldmakers.

When implemented correctly, these newly developed steels will empower moldmakers to excel in competitiveness worldwide.

In the interim, U.S. moldmakers will persist with P20 as they are familiar with its challenges. While costly, their long-standing relationship with P20 allows them to navigate its inherent issues effectively. However, builders should always factor in additional time and expenses in their projects due to common hurdles associated with P20. In a cost-constrained and efficiency-minded economy, optimizing procurement decisions concerning P20 variants is essential for maintaining competitiveness.