Technical Details

For modern industrial production, in particular mass production, machining is one of the most important shaping and forming processes. Almost all tools employed for this purposes are made from high speed steels. In recent times, the use of high speed steels has also gained increasing importance for chip less shaping, example for extrusion, blanking and punching tools. With regard to chemical composition, distinction is made between Tungsten, molybdenum and tungsten molybdenum alloyed steel greats which, depending on the dominant stress they will be exposed to, contain different amount of carbon, vanadium and cobalt. the characteristic properties of all High speed steel greats include:

Influenced of alloying elements on the steel properties :

♦ Carbon - Forms Carbides, increases wear resistance, is responsible for the basic matrix hardness.

♦ Tungsten and Molybdenum - Improved red hardness, retention of hardness and high temperature strength of the matrix, from special Carbides of great hardness.

♦ Vanadium - Forms special Carbides of supreme hardness, increases High temperature wear resistance , retention of hardness and high Temperature strength of the matrix.

♦ Chromium - Promotes depth hardening, produces readily soluble Carbides.

♦ Cobalt - Improves red hardness and retention of hardness of the matrix.

Since it is possible to achieve specific properties by careful adjustment of these alloying elements, we are able to offer the most suitable high speed steel grade for virtually all kinds of application.

Since it is possible to achieve specific properties by careful adjustment of these alloying elements, we are able to offer the most suitable high speed steel great for virtually all kinds of applications.

Raw Material Composition - High Speed Steel

Depending on the application, cutting tools are manufactured using different grades of HSS.

The work material, its hardness, the machine tool used, part configuration, finish required on the Components and volume of components to be produced are the few requirements that influence Selection of different grades of HSS for manufacture of cutting tools.

Chemical composition of some grades of High-Speed Steels normally used is given below :

HSS GRADES CHEMICAL COMPOSITION
  C Cr Mo W V Wo
M2 0.86/0.96 3.8/4.5 4.9/5.5 6.0/6.75 1.7/2.2 Nil
M35 0.88/0.96 3.8/4.5 4.9/5.5 6.0/6.75 1.7/2.2 4.5/5.2
M42 1.05/1.15 3.5/4.5 9.0/10.0 1.3/2.0 1.0/1.03 7.75/8.2
T42 1.25/1.35 3.5/4.5 3.2/4.0 9.5/10.7 2.8/3.5 9.7/10.2
C - Carbon Cr - Chromium Mo – Molybdenum
W - Tungsten Co - Cobalt V - Vanadium

Resharpening Methodology

A Sharp, Correctly ground Drill, will produce more holes, with greater accuracy and finish, more quickly and therefore at low cost.

As point grinding is one of the most major factor in achieving economical and satisfying results, the use of a point strongly recommended. without their use, even the most skilled operator will have difficulty in maintaining the correct Drill Point consistently.

The following three main factor require careful attention when Resharpening.

♦ Lip Clearance - Standard ITM Drills, supplied for general use, incorporate 80 to 120 clearance. The resultant chisel edge angle, as illustrated, is approximately 130 to the cutting edge. If the Lip clearance is excessive, the strength of the Cutters edge is reduced and may result in fracture on the cutting edge. Modification of the Lip Clearance angle is beneficial when Cutters certain materials and recommendations are shown in the table.

♦ Lips (Cutting Edges) - Standard ITM Drills have an included Point angle of 118 degrees. This has been found most suitable for a general propose and should be maintained, ensuring at the same time that the angle is equal on both sides of the center line, so that the length of the lips will also be the same.

If the angles are unequal, the lips will be different lengths. All the work then be done by one cutting edge only resulting in oversize holes been produced and a shorter life for the Drill.

♦ Point Thinning - All ITM Drills are made with a web which increases in thickness towards the shank. When Shortened by repeated grinding, therefore, it is necessary to thin the web at the point in order to maintain the original point thickness.

An equal amount should be ground from each web to ensure it been kept central. The Web thickness at the point can, as a general rule, be taken as been approximately one-eight of the Drill Diameter.