History of the development of high speed steel

In 1898, the American Society of Mechanical Engineers and management Taylor (TaylorF.W.) And metallurgists White (WhiteM.) Developed the invention of high speed steel, and made a cutting test system. When they determine high speed steel components for C-0.67%, W-18.91%, Cr-5.47%, Mn-0.11%, V-0.29%, F- margin, and later W18Cr4V composition is very close. High-speed steel cutting tools available 30m / min cutting speed steel, which is several times more efficient than carbon tool steel and alloy tool steel used in the past, for the United States at the time of the machinery industry won a huge economic benefits.

W18Cr4V speed steel thermoplastic bad, because the twist need hot rolling process, and later the successful development of high-speed steel W6Mo5Cr4V2 addition, there W9Mo3Cr4V. Cutting and mechanical properties of these three high-speed steel approximation, called universal.
After the mid-20th century, the rapid development of science and technology, a variety of difficult materials continue to emerge, the performance of general-purpose high-speed steel no longer use, so high speed steel and high speed steel powder metallurgy have appeared, so the performance of high-speed steel cutting tool material has been greatly improved.

The main products of stainless steel

Antibacterial stainless steel

The authority of the unit testing, antibacterial stainless steel Escherichia coli, Staphylococcus aureus killing rate in more than 99% of other bacteria such as Candida albicans, Kuhei bacteria also have a significant role in the killing, showed excellent broad-spectrum antibacterial and antimicrobial persistence. National Drug and Biological Products detection, inspection showed antibacterial stainless steel in terms of toxicity and human safety in full compliance with national technical standards. At the same time imparting antibacterial properties of stainless steel, mechanics of materials, corrosion, hot and cold processing, welding and other properties of the original stainless steel considerably.
The successful development of antibacterial stainless steel for antibacterial products to provide a broad space for development. Potential antibacterial stainless steel products is huge, very broad market prospects. Today’s society there are many domestic manufacturers expressed interest in antibacterial stainless steel, the group is actively seeking support for the ongoing test for the early bringing the results into products.

Precipitation hardening stainless steel
Has good formability and good weldability, high strength materials as used in the nuclear industry, aviation and aerospace industry.

Cr components can be divided (400 series), Cr-Ni system (300 series), Cr-Mn-Ni (200 series), heat-resistant chromium steel (500 series) and precipitation hardening system (600 series).

200 Series: chrome – manganese – nickel stainless UOL
201, 202 and so on: the generation of nickel and manganese, corrosion resistance is relatively poor, the country is widely used as a cheap alternative to the 300 series
300 Series: chromium – nickel austenitic stainless steel
301: scalability, for molding products. It can also be rapidly hardened by mechanical processing. Good weldability. Abrasion resistance and fatigue strength than 304 stainless steel.
302: 304 with corrosion resistance, due to relatively high carbon intensity and therefore better.
303: by adding a small amount of sulfur and phosphorus to more than 304 cutting.
304: GM models; namely 18/8 stainless steel. Products such as: corrosion resistant containers, utensils, furniture, railings, medical equipment. Standard components are 18% chromium plus 8% nickel. Is non-magnetic, can not borrow from the heat treatment method to change its microstructure of stainless steel structure. GB grades 0Cr18Ni9.
304 L: 304 the same characteristics, but it is more corrosion resistant carbon, easy heat, but less suitable for mechanical welding and heat treatment of the products is not easy.
304 N: 304 with the same characteristics, is a nitrogen-containing stainless steel, add nitrogen to improve the strength of steel.
309: 304 better than temperature resistance, temperature up to 980 ℃.
309 S: with a lot of chrome, nickel, so the heat and oxidation resistance, products such as: heat exchangers, boiler components, jet engine.
310: excellent high temperature oxidation resistance, the maximum temperature 1200 ℃.
316: Following the 304, the second most widely used of steel, mainly used in the food industry, jewelry, watches and clocks, the pharmaceutical industry and surgical equipment, add molybdenum to obtain a special corrosion-resistant structure. Than the 304 because it has better resistance to chloride corrosion and thus as “marine steel” to use. SS316 is often used to fuel recovery. 18/10 grade stainless steel is usually in line with the application level.
316 L: carbon it is more corrosion resistant, easy to heat, products such as: chemical processing equipment, nuclear generators, refrigerant storage worse.
321: In addition to the added titanium elements to reduce the risk of corrosion of the weld material, other properties are similar to 304.
347: Adding stabilization element niobium, suitable for welding aviation equipment parts and chemical equipment.
400 Series: ferritic and martensitic stainless steel, no manganese, to some extent, to replace 304
408: heat resistance, low corrosion resistance, 11% Cr, 8% of Ni.
409: the cheapest model (BAR), commonly used as automobile exhaust pipe, is a ferritic stainless steel (chrome steel).
410: martensitic (high-strength chrome steel), good wear resistance, corrosion resistance is poor.
416: Adding sulfur to improve the processing performance of the material.
420: “Cutting Class” martensitic steel, similar to Brandt’s first high-chromium stainless steel this. Also used in surgical tools, can do very light.
430: ferritic stainless steel, decorative, such as for car accessories. Good shape, but heat resistance and corrosion resistance worse.
440: high strength cutting tool steel, carbon slightly higher, after appropriate heat treatment to obtain a higher yield strength and hardness up to 58HRC, are among the most hard stainless steel. The most common application example is the “razor blades.” There are three commonly used models: 440A, 440B, 440C, in addition to 440F (easy processing).
500 Series: Heat chrome alloy steel.
600 Series: martensitic precipitation hardening stainless steel.