Tool steels simultaneously belong to multiple groups because of its typical characteristics such as high hardness, high toughness, compressive strength and high wear resistance.
Shearing cutters are needed; forging dies; drill bits; molds to form; hammers and chisels to knock. There is steel used for all this. After several years, it was revealed that the cutting speed of the tools could be increased significantly.
Mushet steel is the antecedent of modern steels “high speed”. Today tools for machining, known as cutting tools, are made with high-speed steels. Earlier this century high-speed steels had a high percentage of tungsten, about 18%. They contain chromium, 4%; besides carbon, manganese and silicon.
During World War II and the Korean War, there was a tremendous shortage of tungsten. Molybdenum soon out as a substitute and by the time the armed conflicts had subsided, molybdenum was quite firm in the market.
Modern era of tool steels
Currently, most high-speed steels employ tungsten in place of molybdenum. The high-speed steels of tungsten were designed with a letter “T” and one or two digits. For example, TI and T2 steels were very popular in the twenties and thirties. Now, bits and cutters mechanical workshops steels are made with the “M” series, named for molybdenum.
Hardness Properties For Tool Steels Guillotine Blades
The hardness of tool steel is measured by a pointed object with a certain force. The hardness is expressed by tool steel degrees in Rockwell C, often abbreviated as HRC.
Hardness of Shear Blades
Properties of Shear Blades with different harnesses are as under;
- To 52 HRC: Too soft
- 52-54 HRC: Pretty mild steel, reasonable quality
- 54-56 HRC hardness for regular use in the kitchen
- 56-58 HRC hardness that is used as professional kitchen knives and with this hardness continue to use in the kitchen long sharp enough, just to put on sharpening steel and are easy to sharpen.
- 58-60 HRC hardness you generally encounter in better pocket knives. These knives stay sharp much longer as compared to low-cost knives, but harder to grind.
- 60-62 HRC: Knives with this hardness, long remain sharp and blades are often difficult to grind. With modern steels, these disadvantages are reasonable to suppress it, but the quality is highly dependent on the quality of the entire manufacturing process.
- 63-66 HRC: Currently there are knives available with hardness up to 66. Knives with such hardness have disadvantages such as brittleness resulting in the outbreak of the blade through careless use, and often a low resistance to corrosion.
Apart from the cutting, tool steels are special steels for forming parts and die forgings where, besides the wear resistance, friction is achieved with high tenacity to absorb many blows. Similar properties are expected to shear blades tools and Pierce, which also have a high dimensional stability in heat treatments.
Thing to consider when selecting
The selection of the best tool steel for each type of tool is an art. It is not easy to establish a direct relationship between the addition of a particular alloying steel and feature amending. Moreover, consider factors such as the processing and heat treatment, which often have considerable influence.
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Unfortunately, Mother Nature very unevenly distributed these items, which have become strategic for many countries. They are not strategic for its amount, as the volume of steel produced with these alloying elements is less than 1% of the total. The strategy is that the processing of all steel made in equipment and structures requires tools made from special steel.
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