Jotain is expert in exporting steel products.we not only have the great advantages in our product quality/price/resource/service,but also have absolute advantages in our technical aspects.



Steels can exhibit a wide variety of properties depending on composition as well as the phases and microconstituents present, which in turn depend on the various types of heat treatment such as annealing, normalizing, and quenching plus tempering, etc.

Jotain has dedicated in steel heat treatment industrial since 2000. Starting from one military department providing quenched and tempered steel parts,it has grown up into the most experienced and capable supplie of heat treatment steel products.

Typical Steel Grade


Delivery condition: Hot rolled, Normalized, Quenched and tempered, Annealed, Spheroidized;Peeled, Turned, Black, Black skin, Milled, Carbonized.

Facilities List

The furnaces commonly used for heat treating of steels are classified in two broad categories, batch furnaces and continuous furnaces. The batch furnace normally consists of an insulated chamber with an external reinforced steel shell, a heating system for the chamber, and one or more access doors to the heated chamber. During the operation, workpieces normally are mechanically loaded and unloaded into and out of the furnaces chamber which are normally used:

  • To handle special parts for which it would be difficult to adapt a conveying system for ontinuous handling;

  • To process large parts in small numbers;

  • To process various parts requiring a wide range of heat-treat cycles that can readily be changed, either manually or automatically;

  • To be heated from room temperature to a maximum temperature at controlled rates, held at temperature, and cooled at controlled rates.

Continuous furnaces consist of the same basic components as batch furnaces: an insulated chamber, heating system, and access doors. In continuous furnaces, the furnaces operate in uninterrupted cycles as the workpieces move through them, so they are readily adaptable to automation and thus are generally used for big quantity workpieces. Another advantage of continuous furnaces is the precise repetition of time-temperature cycles, which are a function of the rate of travel through the various furnace zones.

Continuous Furnace №1

Furnace type:  automatic controlled gas heating O-Type

Design by:  SMS Ares

Application:  normalizing, quenching & tempering

Maximum workpiece dimension:  250mm in diameter, 15m in length

Continuous Furnace №2

Furnace type:  medium frequency induction

Application:  normalizing, quenching & tempering

Maximum workpiece dimension:  240mm in diameter, 13.5m in length

Continuous Furnace №3

Furnace type:  medium frequency induction

Application:  normalizing, quenching & tempering

Maximum workpiece dimension:  120mm in diameter, 18m in length

Continuous Furnace №4

Furnace type:  medium frequency induction

Application:  normalizing, quenching & tempering

Maximum workpiece dimension:  70mm in diameter, 12m in length

Continuous Furnace №5

Furnace type:  medium frequency induction

Application:  normalizing, quenching & tempering

Maximum workpiece dimension:  120mm in diameter, 12m in length

Batch Quenching Furnace №1

Furnace type:  car-bottom with controlled gas heating

Application:  quenching

Maximum workpiece:  15 tonnes

Batch Quenching Furnace №2

Furnace type:  resistance heating

Application:  quenching

Maximum workpiece:  20 tonnes

Batch Tempering Furnace №1

Furnace type:  resistance heating

Application:  tempering

Maximum workpiece dimension:  13.5m×1.6m×1.2m

Batch Tempering Furnace №2

Furnace type:  resistance heating

Application:  tempering

Maximum single workpiece:  20 tonnes

Batch Tempering Furnace №3

Furnace type:  resistance heating

Application:  tempering

Maximum single workpiece:  15 tonnes

Batch Treatment Furnace №1

Furnace type: resistance heating

Application: quenching&tempering, normalizing, annealing

Maximum workpiece dimension: 6.0m×1.6m×1.2m

Batch Treatment Furnace №2

Furnace type:  resistance heating

Application:  quenching&tempering, normalizing, annealing

Maximum workpiece dimension:  7.0m×1.8m×1.5m

Special steel bar:

Diameter:  25mm~300mm Hot roll.

Length:  3,000mm~15,000mm.

Diameter:  150~1300mm Forged bar.

Length:  3,000mm~11,800mm.

Stress-Relief Heat Treating of Steel

 Stress-relief heat treating is used to relieve stresses that remain locked in a structure as a consequence of a manufacturing sequence. This heat treating is the uniform heating of a structure, or portion thereof, to a suitable temperature below the transformation range, holding at this temperature for a predetermined period of time, followed by uniform cooling. Care must be taken to ensure uniform cooling, particularly when a component is composed of variable section sizes. If the rate of cooling is not constant and uniform, new residual stresses can result that are equal to or greater than those that the heat treating process was intended to relieve.

Normalizing of Steel

 Normalizing of steel is a heat treating process that is often considered from both thermal and microstructural standpoints. In the thermal sense, normalizing is an austenitizing heating cycle followed by cooling in still or slightly agitated air. Typically, the work is heated to a temperature about 55 °C (100 °F) above the upper critical line of the iron-iron carbide phase diagram or above Ac3 for hypoeutectoid steels and above Acm for hypereutectoid steels. Normalizing is also frequently thought of in terms of microstructure. The steels of the microstructure that contain about 0.77% C are pearlitic and that are low in carbon are ferritic, but in hypereutectoid steels, proeutectoid iron carbide first forms along austenite grain boundaries. This transformation continues until the carbon level in the austenite reaches approximately 0.77%, at which time a eutectoid reaction begins as indicated by the formation of pearlite. The purpose of normalizing varies considerably. Normalization may increase or decrease the strength and hardness of a given steel in a given product form, depending on the thermal and mechanical history of the product.

Annealing of Steel

Annealing is a generic term denoting a treatment that consists of heating to and holding at a suitable temperature followed by cooling at an appropriate rate, primarily for the softening of metallic materials. Generally, in plain carbon steels, annealing produces a ferrite-pearlite microstructure. Steels may be annealed to facilitate cold working or machining, to improve mechanical or electrical properties, or to promote dimensional stability. The choice of an annealing treatment that will provide an adequate combination of such properties at minimum expense often involves a compromise. In practice, specific thermal cycles of an almost infinite variety are used to achieve the various goals of annealing. These cycles fall into several broad categories that can be classified according to the temperature to which the steel is heated and the method of cooling used.

Quenching of Steel

Quenching refers to the process of rapidly cooling metal products from the austenitizing or solution treating temperature, typically from within the range of 815 to 870 °C (1500 to 1600 °F) for steel. Stainless and high-alloy steels may be quenched to minimize the presence of grain boundary carbides or to improve the ferrite distribution but most steels including carbon, low-alloy, and tool steels, are quenched to produce controlled amounts of martensite in the microstructure. Successful hardening usually means achieving the required microstructure, hardness, strength, or toughness while minimizing residual stress, distortion, and the possibility of cracking. The selection of a quenchant medium depends on the hardenability of the particular alloy, the section thickness and shape involved, and the cooling rates needed to achieve the desired microstructure. The ability of a quenchant to harden steel depends on the cooling characteristics of the quenching medium. Quenching effectiveness is dependent on the steel composition, type of quenchant, or the quenchant use conditions.

Tempering of Steel

Tempering of steel is a process in which previously hardened or normalized steel is usually heated to a temperature below the low critical temperature and cooled at a suitable rate, primarily to increase ductility and toughness, but also to increase the grain size of the matrix. Steels are tempered by reheating after hardening to obtain specific values of mechanical properties and also to relieve quenching stresses and to ensure dimensional stability. Tempering usually follows quenching from above the upper critical temperature; however, tempering is also used to relieve the stresses and reduce the hardness developed during welding and to relieve stresses induced by forming and machining. 

Martempering of Steel

Martempering is a term used to describe an interrupted quench from the austenitizing temperature of certain alloy, cast, tool, and stainless steels. The purpose is to delay the cooling just above the martensitic transformation for a length of time to equalize the temperature throughout the piece. This will minimize the distortion, cracking, and residual stress. 

Austempering of Steel

Austempering is the isothermal transformation of a ferrous alloy at temperature below that of pearlite formation and above that of martensite formation. Austempering of steel offers several potential advantages: increased ductility, toughness, and strength at a given hardness; reduced distortion, which lessens subsequent machining time, stock removal, sorting, inspection, and scrap; the shortest overall time cycle to through-harden within the hardness range of 35 to 55 HRC, with resulting savings in energy and capital investment.

Spheroidizing of Steel

The majority of all spheroidizing activity is performed for improving the cold formability of steels. It is also performed to improve the machinability of hypereutectoid steels, as well as tool steels. After spheroidizing, that is, heated and cooled to produce a structure of globular carbides in a ferritic matrix. A spheroidized microstructure is desirable for cold forming because it lowers the flow stress of the material. The flow stress is determined by the proportion and distribution of ferrite and carbides. The strength of the ferrite depends on its grain size and the rate of cooling. Whether the carbides are present as lamellae in pearlite or spheroids radically affects the formability of steel. 

Heat Treating of Ultrahigh-Strength Steels

Ultrahigh-strength steels are heat treated by use of equipment and techniques similar to those employed for heat treating constructional alloy steels. With ultrahigh-strength steels, emphasis is placed on the maximum section size that a given alloy will respond to during heat treatment, and thus machining is generally done prior to heat treatment to optimize final property response. The ultrahigh-strength steels ordinarily are quenched and tempered to specific hardness, but for critical applications it may be necessary to pull tensile specimens to ensure that a required combination of strength and ductility has been achieved. In still other instances, it may be necessary to conduct impact or fracture-toughness tests to ensure that a required level of resistance to brittle fracture has been attained. The majority of ultrahigh-strength steels are available in varying quality levels. The quality level is usually dictated by the method of primary or secondary melting used in the manufacture of that alloy. The widely used in refining techniques such as argon-oxygen decarburization (AOD) and vacuum oxygen decarburization (VOD) along with vacuum induction melting (VIM) as primary melting techniques. Remelting is typically performed with vacuum arc remelting (VAR) techniques to further enhance microstructural cleanliness. Currently some of the grades are being processed by electroslag remelting (ESR). Although heat treatment of the different quality level materials is similar, the premium quality provides increased fracture toughness, tensile ductility, and fatigue life at a given strength level.

Heat Treating of Maraging Steels

Maraging steels are highly alloyed low-carbon iron-nickel martensites that process an excellent combination of strength and toughness superior to that of carbon-hardened steel. As such, they constitute an alternative to hardened carbon steels in critical applications when high strength and good toughness and ductility are required. Hardened carbon steels derive their strength from transformation-hardening mechanisms (such as martensite and bainite formation) and the subsequent precipitation of carbides during tempering. In contract, maraging steels derive their strength from the formation of a very low-carbon, tough, and ductile iron-nickel martensite, which can be further strengthened by subsequent precipitation of intermetallic compounds during age hardening.

Thermomechanical Processing of Steels

Economic and technical demands have forced the globe steel industry to undergo a series of important changes. These changes were made imperative by the need of the steel industry to maintain a competitive and leadership position in relation to other engineering materials. Significant advances have been made in both process metallurgy and product metallurgy. These advances have transferred the steel industry into a modern, cost-effective, and high-quality manufacturing force in the world marketplace. The improvements in steelmaking, ladle refining and continuous casting practices have been matched with other advances in the science and technology of microstructural control in the final product. It is this ability to control microstructure during processing that has allowed significant and cost-effective improvements in the final properties of steel to be achieved. Central to the concept of controlled processing is thermomechanical controlled processing (TMCP). It is a procedure in which both the temperatures and size reductions are strictly controlled and in which rolling is completed at a specified temperature close to, and may be less than, that at which ferrite formation is complete. This results in a microstructure and mechanical properties which cannot be obtained by a normalizing heat treatment. Because the goal of thermomechanical processing is the refinement of the austenite grain structure, the control of recrystallization and/or grain coarsening during processing are among the metallurgical techniques available. The presence of minute quantities of elements such as niobium, titanium, and vanadium have been shown to be particularly useful during thermomechanical processing because of the change in the solubilities of their carbides /carbonitrides/nitrides in austenite as a function of temperature. These elements are known as microalloying elements (MAE) because they are generally present at levels at or below 0.1 wt%. Hence, the use of these microalloying elements enables the goal of thermomechanical processing to be easily achieved because these elements permit forces retarding recrystallization and grain coarsening to be governed by controlled precipitation during processing.