Tool and steels:
Tool and die steels are specially alloyed steels that are used in metal forming and machining because of their high strength, impact toughness, and wear resistance at room and elevated temperatures.
The main categories of these materials are described as follows:
1. High-speed steels (HSS) are the most highly alloyed tool and die steels that retain hardness and strength at high operating temperatures. High-speed steels are classified into two types: molybdenum (M series) and tungsten (W series) (T series). When compared to T-series steels, M-series steels have higher abrasion resistance, less distortion during heat treatment, and are less expensive.
2. Hot-work steels (H-Series) have high toughness and resistance to wear and cracking and are designed for use at elevated temperatures. Wrought iron, molybdenum, chromium, and vanadium are common alloying elements.
3. Cold-work steels (A, D, and O series) are used for cold-working operations and have a high resistance to wear and cracking. These steels are available as oil-hardening or air-hardening types.
4. Shock-resistance steels (S series) are designed for impact toughness and are used in applications such as header dies, punches, and chisels. Other properties of these steels vary depending on their composition.
5. Special Purpose steels are made to meet the specifications of zinc die casting and plastic injection molding dies. Low alloy special purpose tool steel is abbreviated as L-Type tool steel. L6 is a very tough material. Water-hardened F-type tool steel is significantly more wear-resistant than W-type tool steel.
6. Water hardening, is basically high-carbon steel. While it generally has a lower cost it cannot be used where high temperatures are involved. This steel can achieve high hardness, but it is rather brittle when compared to other tool steels. All W-Grade tool steels must be water quenched, which can lead to increased warping and cracking. Typical applications of W-Grade tool steel include Cold Heading, Cutting tools and knives, Embossing, Reamers, and Cutlery.
7. Water hardening, essentially high carbon steel. While it is generally less expensive, it cannot be used in situations involving high temperatures. This steel has a high hardness but is brittle when compared to other tool steels. Water quenching is required for all W-Grade tool steels, which can cause increased warping and cracking. W-Grade tool steel is commonly used in Cold Heading, Cutting tools and knives, Embossing, Reamers, and Cutlery.
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