Investigation of the structure and chemical composition of the metalcutting tool supplied to Ukraine market

Abstract

There search of cutting tools from different supplier to establish their responsibility with thees sential requirements was conducted in the work. Metal-cutting tools of  the domestic instrumental works (taken as the standard through certification in Ukr NDI Spetsstal) and foreign producers were chosen for studying made of high speed steel R6M5, which confirmed the label on the product. It was analyzed the chemical composition and the structure of the material to determine the requirements of state standards. It was stated a number of differences in comparis on with the microstructure of the studied steels samples. There are both large on tents of primary carbides and secondary discharge dispersion strengthening phase in the structure of materials which are equally divided the cross-section of thin sections. A difference in the size, nature of the distribution and morphology of carbide compounds is fixed. Carbide banding is retraced at one of the samples which may indicate the violation of the preliminary heat treatment technology at the stage of getting the piece. The volume fraction of secondary substances in samples of foreign tools is somewhat lower as compared with reference that may be the result of an under valued content of refractory carbide elements as tungsten, vanadium, molybdenum according to indicated grade composition and influence the preliminary durability of cutting tools.

The chemical composition of samples of products of foreign and standard manufacturers is studied. Thees sential difference in the concentration of alloying elements content of three products made by the manufacturer of the material is determined. A fundamental difference in the content of tungsten and molybdenum at 1.5...2 % was recorded as compared with reference material and standard. Under stated amount of alloying elements is directly connected with an attempt of the manufactures to reduce the production cost of high-speed tools despite reducing of itsstability.

The chemical composition of the reference sample corresponded to the stated brand steel, respectively, had a positive impact on the structure required for high-speed machining of high strength materials.

It is found on the base of the given data of the chemical composition of products manufactured abroad that the closestgrade as to the quantitative content of alloying elements are steel type R3M3F2. This steel can be used for carbons teel machining and low-alloyed tensile strength of not more than 780 M Pain the high control of temperature during heating operation.

A number of products with a low content of alloying elements are offered in the Ukraine market which leads to increasing material costs of engineering enterprises. Therefore, to prevent the purchase of low-quality products, enterprises should introduce strict quality control of tools for metal working.