Carbon Steel Treatment

Heat treatment of steel can make carbon steel change their steel’s physical and mechanical properties without the change of original shape and size. The process of this treatment just by heating and cooling in right way of carbon steel.

Heat treatment process can use to increase the strength of steel but also can use to soften the steel. Heat treatment also can alter certain manufacturability objectives such as improve machinability, formability, restore the ductility, etc. So heat treatment process is very important in industrial that produce product from steel and also many industrial practice that maintain and steel before they use. High carbon steel are particularly suitable for heat treatment, since carbon steel respond well to heat treatment and the commercial use of steels exceeds that of any other material.

Here are the steel treatment that usually use in metal industrial processes:

• Annealing
• Hardening and tempering of tool steel
• Heat treatment of Low-Alloy Cold Work Tool Steels
• Heat treatment of Low Alloy Cold Work and Hot Work Tool Steels
• Surface Hardening of Steels
• Carburizing
• Nitriding
• The Tempering of Martensite
• The tempering of alloy steels
• Gas Nitriding

Honing Process

Honing is a process of machining with bonded abrasive grains. It serves to improve the shape, size, accuracy and surface quality of the work piece. So this often time use if car cylinder head uneven.

One distinguishes between long stroke honing and short stroke honing (superfinishing). In terms of the movement cycles. Both processes can’t be used for internal surface (holes) as well as for outer surfaces (shaft).

Long stroke honing (honing).
The honing foot has four or more honing sticks mounted in it. The foot rotates and goes through an axial stroke motion at the same time. The stroke length is set so that the tool moves upward and downward beyond the workpiece by about ¼ of the own length. These motions combine to form a helical grinding track. This not only improves the surface quality, but also the cylindrical shape of the honed workpiece. This process does not significantly affect the roundness of holes. The honing sticks are pressed and fed against the generated surface by two cones inside the tool.

On the honing machine, the workpiece (engine block, brush, etc.) travel under the honing tool on a table which moves and endwise and crosswise. The honing tool is suspended in the honing spindle with a ball and socket joint so that it can move and adjust to the position of the hole. The rotary motion of the spindle is imparted to it by an electric motor over a steplessly variable belt or chain drive. The stroke motion is generated hydraulically, and can be regulated in length, position and speed.

Because it must adjust precisely to the axial position of the hole being honed, the honing tool cannot be rigidly fixed to the spindle. A ball and socket joint is therefore interposed between the spindle and the tool (cardanic suspension).

Superfinishing




This process is characterised by a third movement. In addition to the rotation of the workpiece and the stroke movement of the tool (honing block), the tool also reciprocates through a distance of 1 to 5 mm at 700 to 1500 cycles per minutes. The grinding track is a continuous wavy spiral. The curvature of the honing block is matched to the workpiece diameter, so that the threshold movement improves the circularity as well as cylindrical shape or the workpiece.

In both processe, longer and broader honing blocks (i.e. of greater surface area), improve the shape of the workpiece. The infeed pressure is however, reduced when the tool is of greater area, which increases production time.

Casting Process

A large part of steel produced is cast iron ingots and bars. Further processing then takes the for of forging, rolling or extrusion.

In monoblock casting, the molten steel is poured into moods. In continuous casting, the metal is cast in an open water cooled mold. Losing heat in the mold, the steel solidifies and is lowered in the form of a bar between holding and supporting rollers (pinch roll). The lowering speed can be up to 2 m/min. The high speed of solidification of the bars hinders segregation and the formation of gas cavities or shrinkage cavities, resulting in greater uniformity of structure.

After the development of continuous casting the older practice of cogging (rolling ingots derived from static moulding after heating them to incandescence in a crucible furnace) has been rendered obsolete. The bar cross sections can be adjusted to suit the shape of the finished product for which the steel is destined, reducing the extent of subsequent forming work required.

Casting materials

Casting materials are iron carbon alloys with around 2% to 4% carbon, whose properties suit them for the production of shaped casting.

Some materials falling into this category are: cast iron with lamellar graphite (GG), cast iron with nodular graphite (GGG), chilled iron (GH), malleable cast iron (GTW and GTS). These are melted in foundry shaft furnace.

Carbon Steel Fining

Fining is the process of removing traces of the so-called iron companions P, Si, Mn and reducing the carbon content to the desired level.

Small quantities of sulphur and phosphorus are heated in crucible. The sulphur combines with atmosphere oxygen burning with a blue flame to produce SO2 (liquid odor). The yellow phosphorus ignites when heated even slightly (caution). A white phoporus pentoxide (P2O3) is produced.

Steel is the result of chemical changes in pig iron when it is heated to temperature above 1600oC. The carbon is released as carbon dioxide in the process, and the sulphur and phoporus absorbed in the slag.

If air or oxygen is passed through the melt, phosphorus is oxidised to phosphorus pentoxide, sulphur to sulphur dioxide, silicon to silicon dioxide, manganese to manganese oxide and carbon to carbon dioxide.

Oxygen Conversion Process
The best known is the LD-process, named alter the Austrian steel works in Linz Donawitz.

About 70% of all steel used is produced by the oxygen conversion process, since it is more economical than the Siemen Martin (open hearth) process.

The LD-converter is charged with molten pig iron, sponge iron, scrap and additions.

Oxygen is blown through a water-cooled lance (steel pipe) on to the melt, at an overpressure of around 12 bar. The oxidation of carbon and iron companions generates a considerable quantity of heat, which sets the melt into violent motion. The excess heat is neutralized by adding cold scrap. Lime is added to bind the oxidised iron companions, such as manganese, silicon, phosphorus and sulphur into slag.

Alloying elements are added to improve the quality at the end of the lining process or while tapping. The steel thus produced is known as basic oxygen steel.

Other posts:

• Unalloyed and alloyed steel
• Electric Steel making process 

Heat Treatment to Carbon Steel

As the material technology. for many low-alloy steels, the primary function of the alloying elements is to increase hardened ability in order to optimize mechanical properties and toughness after heat treatment. In some cases, however, alloy additions are used to reduce environmental degradation under certain specified service conditions.

As with steels in general, low-alloy steels can be classiified according to Chemical composition, such as nickel steels, nickel chromium steels, molybdenum steels, chromium molybdenum steels.

Heat treatment, such as quenched and tempered, normalized and tempered, annealed. Because of the wide variety of chemical composition possible and the fact that some steels are used in more than one heat-treated, condition, some overlap exists among the alloy steel classifications.

There are four groups of alloy steels are addressed:

• Low Carbon quenched and tempered (QT) steels
• Medium-carbon ultrhigh strength steels
• Bearing steels
• Heat resistant chromium molybdenum steels

Other articles:

• Stainless composition and history
• Basic steel grade and structural steel 

Metal Pretreatment

Paint and plastic stripping have never been easier to treatment before they are become a raw material to the next process. The technology continues to improve this difficulties on processing and has revolutionized the way to strip organic from metal parts. The Dynamic Fluid Clean is the answer to your cleaning hassles.

The parts to be stripped are immersed in a hot fluidized sand bed which is heated up to 420 – 450 ^oC. The organic adhering the metal parts will be removed without creating environmental pollution. The total cleaning time is less one hour. Typical parts to be cleaned are paint, hangers, grates, dies, nozzles, extrusion, screw, etc.

With more than 450 reference world-wide, the Dynamic Fluid Clean has been recognized as the absolute solution for stripping paint, plastic, rubber, and other materials from metal parts.

Other articles:

• Corrosion problem
• Forged carbon steel products