What is steel?
Steel is made by removing oxygen and other impurities from iron ore. When iron is combined with carbon, recycled steel and small amounts of other elements it becomes steel.
Steel is an alloy of iron and carbon containing less than 2% carbon and 1% manganese and small amounts of silicon, phosphorus, sulphur and oxygen.
Steel is the world’s most important engineering and construction material. It is used in every aspect of our lives; in cars and construction products, refrigerators and washing machines, cargo ships and surgical scalpels.
All steel contains carbon, but carbon steel is unique for a notable absence of other elements in its makeup. Though it only contains 2% carbon or less by weight, its elemental nature makes carbon steel a strong, durable material that is ideal for numerous uses.
Carbon steel is sometimes confused with cast iron, though it must contain less than 2% carbon. Cast iron contains 2% to 3.5% carbon, giving it a rough texture and more brittle nature.
Even though carbon steel is composed of alloyed metals, it doesn’t have alloy classification because of the lack of other alloying elements in its composition. This simplicity contributes to carbon steel’s popularity — it accounts for about 90% of all steel production.
Below the 2% carbon threshold, carbon steel can be grouped into three categories: low, medium, and high carbon. Each type retains the inherent strength of carbon, but its useful purpose will change as the carbon content increases.
- Low carbon: This is the most common and the least expensive type. It’s easy to form due to its high ductility — its innate ability to be stretched under strain. Wires, bolts and pipes use this type of steel.
- Medium carbon: A carbon content between 0.31% and 0.60% gives this variety a higher strength and lower ductility than lower carbon varieties. Medium carbons are found in gears and railroad tracks.
- High carbon: The toughest variety is more than 0.61% carbon and is often used to produce brick nails and sharp cutting tools like trencher blades. They do not contain more than 2% carbon.
Carbon steel’s relative adaptability and low cost make it an ideal choice for a variety of construction projects, both large and small-scale.
Cementation steels are low carbon, unalloyed or alloy steels used in the manufacture of parts that are hard and wear-resistant on the surface and softer and toughness properties are desired in the core, and are resistant to variable and impact forces. These features are given to the part by impregnating carbon on the steel surface. Cementation steels are used in the manufacture of parts such as gears, shafts, piston pins, chain links, sprockets and pulleys, discs, guide bearings, roller bearings, rollers, some measuring and control tools, medium forced parts, cutting tools. Cementation process is applied to harden case hardening steels. During this process, carbon is absorbed on the surface of the material at high temperature. The machining process is very easy, as the cementation process is applied after the part has been completely or partially finished. If there are areas on the surface of the part that will be processed later and do not have to harden, these areas are covered by covering with special paste or electrolytic copper. Since carbon cannot penetrate these areas, the part can be easily processed later. Since the core area of the material will maintain its softness after hardening with cementation, it becomes quite resistant to impacts.
Cementation steels are much cheaper than high carbon steels, which can give the same hardness on the surface and are in the tool steel class. However, the selection of the cementation steel and the correct cementation process should bring a lot of attention and experience. Good results of the cementation process is closely related to the internal structure cleaning of the steel used. Internal structure cleaning is also the process of purifying from gases (hydrogen, oxygen, nitrogen) dissolved in liquid, and cleaning from oxides and sulfur inclusions. In general, the depth of the cementation layer can be between 0.2 and 1.5 mm at the end of the cementation process. In the surface hardening process, fatigue life increases as the depth of the cementation layer increases. Fatigue is the amount of carbon element most affected by its life. The amount of carbon dissolved in the austenite phase is the most important factor affecting surface hardness. The amount of carbon on the surface should be controlled to be between 0.80% and 1.0%.
As the cross-section of the material used grows, higher alloy steels should be used. The characteristic usage area of these steels is gear manufacturing, and can be called GEAR STEELS by their usage. The important thing in gears is high wear fatigue resistance.
Reconditioning steels are alloyed and unalloyed machine-building steels that are suitable for hardening, especially in terms of carbon content, and show high toughness at a certain tensile strength at the end of the curing process. The curing process is described as a combination of first hardening and then tempering processes, to impart high toughness to the steel part. Due to the superior mechanical properties they gain at the end of the treatment process, curing steels are mainly used in the manufacture of various machine and engine parts, forging parts, nuts, bolts and studs, crankshafts, axles, control and drive parts, piston rods, various shafts, gears and shafts. They form an important part of machine-manufacturing parts.
The selection of the appropriate breeding steel and the application of the correct breeding process is an event that requires a lot of attention and experience. The good results of the reclamation process (reaching the desired hardness and toughness values) are closely related to the internal structure cleaning of the steel used. Internal structure cleaning is related to the purification of liquid steel from impurities (such as hydrogen, oxygen, nitrogen) dissolved in its body and cleaning it from oxide and sulfur inclusions.
Free Cutting Steel
Free cutting steels also known as free machining steels are suitable for mass production of machine parts due to their excellent machinability property. This property is mainly result of sulphur and lead elements in the steel composition. Sulfur enables the fragmentation of the chip and lead reduces the friction between the tool and piece. Free cutting steels are commonly used in automotive industry and house appliance industry.
Stainless / Inox Steel
stainless steel, any one of a family of alloy steels usually containing 10 to 30 percent chromium. In conjunction with low carbon content, chromium imparts remarkable resistance to corrosion and heat. Other elements, such as nickel, molybdenum, titanium, aluminum, niobium, copper, nitrogen, sulfur, phosphorus, or selenium, may be added to increase corrosion resistance to specific environments, enhance oxidation resistance, and impart special characteristics.
Most stainless steels are first melted in electric-arc or basic oxygen furnaces and subsequently refined in another steelmaking vessel, mainly to lower the carbon content. In the argon-oxygen decarburization process, a mixture of oxygen and argon gas is injected into the liquid steel. By varying the ratio of oxygen and argon, it is possible to remove carbon to controlled levels by oxidizing it to carbon monoxide without also oxidizing and losing expensive chromium. Thus, cheaper raw materials, such as high-carbon ferrochromium, may be used in the initial melting operation.
There are more than 100 grades of stainless steel. The majority are classified into five major groups in the family of stainless steels: austenitic, ferritic, martensitic, duplex, and precipitation-hardening. Austenitic steels, which contain 16 to 26 percent chromium and up to 35 percent nickel, usually have the highest corrosion resistance. They are not hardenable by heat treatment and are nonmagnetic. The most common type is the 18/8, or 304, grade, which contains 18 percent chromium and 8 percent nickel. Typical applications include aircraft and the dairy and food-processing industries. Standard ferritic steels contain 10.5 to 27 percent chromium and are nickel-free; because of their low carbon content (less than 0.2 percent), they are not hardenable by heat treatment and have less critical anticorrosion applications, such as architectural and auto trim. Martensitic steels typically contain 11.5 to 18 percent chromium and up to 1.2 percent carbon with nickel sometimes added. They are hardenable by heat treatment, have modest corrosion resistance, and are employed in cutlery, surgical instruments, wrenches, and turbines. Duplex stainless steels are a combination of austenitic and ferritic stainless steels in equal amounts; they contain 21 to 27 percent chromium, 1.35 to 8 percent nickel, 0.05 to 3 percent copper, and 0.05 to 5 percent molybdenum. Duplex stainless steels are stronger and more resistant to corrosion than austenitic and ferritic stainless steels, which makes them useful in storage-tank construction, chemical processing, and containers for transporting chemicals. Precipitation-hardening stainless steel is characterized by its strength, which stems from the addition of aluminum, copper, and niobium to the alloy in amounts less than 0.5 percent of the alloy’s total mass. It is comparable to austenitic stainless steel with respect to its corrosion resistance, and it contains 15 to 17.5 percent chromium, 3 to 5 percent nickel, and 3 to 5 percent copper. Precipitation-hardening stainless steel is used in the construction of long shafts.
Bearing steel is special steel featuring high wear resistance and rolling fatigue strength. High-carbon chromium bearing steel, engineering steel and some types of stainless steel and heat resistant steel are used as materials of bearings and for other purposes.
Sanyo Special Steel takes advantage of the high-cleanliness steel production technology in achieving the world’s top cleanliness and leads the bearing steel industry because of its high quality and reliability. We have also established a system to produce and offer steel bars, wire rods, tubes and formed and fabricated materials that match the process of each customer in terms of shape.
Spring steel is a name given to a wide range of steels used in the manufacture of springs, prominently in automotive and industrial suspension applications. These steels are generally low-alloy manganese, medium-carbon steel or high-carbon steel with a very high yield strength. This allows objects made of spring steel to return to their original shape despite significant deflection or twisting. For springs that are exposed to fatigue loads, high demands are placed on surface finish and inner cleanness (limitation of amount of non-metallic inclusions).
Cold Drawing Steel
We export cold drawn bright steel products with 0.5 mm/mt straightness and in accordance with IT 9 tolerance, EN 10278. Whether it is coil to bar or bar to bar drawing, all cold drawn bright steel products we export meet customers’ expectations for mechanical properties.
We supply both coil-to-bar and bar-to-bar cold drawn products, starting with wire diameters up to 55-60 mm.
We export hot rolled steel bars, stripped bright steel bars from 18.00 mm up to 200.00 mm with tolerance up to IT9.
We export grinded bright steels in diameter ranges from 20.00 mm to 80.00 mm. These bars are produced from low carbon alloy steels.