JP4281000B2 - Steel for cutting tools - Google Patents

Abstract

A steel composition comprises (wt.%): 0.88-1.12 carbon; 3.4-4.5 chromium; 2.5-3.0 molybdenum; 0.7-1.0 vanadium; 0.04-0.1 aluminum; 0.02-0.12 nitrogen; and balance manganese, silicon, iron and residual impurities.

Description

  The present invention relates to steel for cutting tools.

The tool blade area or blade portion is substantially loaded with respect to heat, wear, toughness and compressive load during the removal of workpiece debris and the tool material is loaded simultaneously. In order to obtain the maximum tool life at different load profiles, the respective alloy compositions that take into account the advanced requirements in the profile belong widely to the prior art.

  The high tool blade life is generally obtained by the use of high-speed steel, which contains a high content of expensive alloying elements molybdenum and / or tungsten in concentrations up to 20% by weight. Vanadium also belongs to these elements and is added to ordinary high speed steel or PM high speed steel having a content of 1.2 to 10.0% by weight.

  As mentioned above, high speed steel is advantageously chosen for the load profile required for the tool in terms of composition, but has the disadvantage of high alloy costs and thus material costs. Now, for economic reasons, when the concentration of the main alloying element is reduced, the heat-treatability, hardness, and generally the use characteristics of the steel can often be drastically deteriorated.

  The problem underlying the present invention is to eliminate the disadvantages of the prior art and to provide a steel with a particularly good suitability for cutting tools and a high degree of economics by means of alloying technology. .

This problem is the following element C = 0.88 to 1.12 by mass
Si = 0.15 to 0.42
Mn = 0.15 to 0.44
P = 0.03 or less Cr = 3.4-4.5
Mo = 2.5-3.0
V = 0.7 to 1.0
Al = 0.04-0.1
N = 0.02 to 0.12
And the steel for cutting tools consisting of iron and impurity elements as the balance.

  The advantages afforded by the present invention are largely over the prior art due to the combination of the elements molybdenum and vanadium on the one hand, and on the other hand at a significantly lower concentration than high speed steel, due to the content of aluminum and nitrogen. With a relatively high content, advantageous high temperature strength and high wear resistance are obtained with sufficient toughness and compressive load of the heat treated steel. A cutting tool made of an alloy according to the invention is economically manufacturable due to the low content of expensive elemental metals, but has high durability even for special requirements in the load profile.

Chip evacuation in the area after the rake face or cutting edge of the tool formed from the steel according to the invention is more conveniently performed, and crater formation, i.e. the removal of tool material on the rake face by the evacuated swarf is significantly reduced. The reason is not yet scientifically understood, but it seems to be explained by the synergistic effects of the elements aluminum, nitrogen, carbon and vanadium. The high affinity of vanadium for carbon and nitrogen, which results in advantageously high temperature strength during heat treatment due to the formation of the finest and homogeneously distributed carbides and nitrides, leaves sufficient amounts of reactive aluminum in the substrate. This aluminum can, to some extent, form an alumina surface layer, i.e., a coating that promotes chip evacuation, upon oxidation during thermal loading in the tool blade range. As can be seen, the aluminum in the substrate also helps the high temperature strength and annealing stability of the material according to the invention.

Vanadium, can be replaced by niobium up to some 0.45 mass% in the alloy, the carbon content in this case should be set to the lower range of concentration limits.

According to the present invention in a preferred embodiment, Ru following concentration ranges near mass% following elements C = 0.93 ~1.07
Al = 0.05 to 0.07
N = 0.03-0.1
It is contemplated to use steel containing for cutting tools.

  The use of a considered concentration range of elements in the alloy can further enhance a particularly important range in the tool property profile.

If the ratio of aluminum to nitrogen (Al / N) is between 0.5 and 1.9, the material according to the invention is at least 1 in the heat-treated state, ie in the range between quenching and 450 ° C. and 500 ° C. After tempering once, it has high high temperature strength and toughness and very little rake face wear on the tool.

A metal cutting circular saw with a hardness greater than 63 HRC, in particular greater than 64 HRC, can be produced from the steel according to the invention, particularly economically with a long life in severe use.

Examples of the invention which show only the composition of the steel in comparison with commonly used materials according to German Industrial Standard No. 1.3343 are described in detail below. A plurality of circular saw plate having a heat-treated teeth as having and described above the diameter of 400mm is tightened at intervals on a common axis, dividing the toughness metal bar simultaneously to multiple pieces.

  Between saw blades made of an alloy which have proved advantageous with respect to the life of the saw blade and are indicated in Table 1 with the designation TypA1, Vers. A saw blade made of an alloy according to the invention indicated by L3 was inserted.

Until separated from the saw shaft for wear, compared expert in Table 2 is performed, the results in Table 2 Karawakari, the value of TypA1 is indicated by 100%. As can be seen from the results, a high cutting ability is obtained when the material according to the invention is used for cutting tools, in particular circular saws.

Claims (4)

The next element in mass% C = 0.88~1.12
Si = 0.15 to 0.42
Mn = 0.15 to 0.44
P = 0.03 or less S = 0.001-0.3
Cr = 3.4 to 4.5
Mo = 2.5-3.0
V = 0.7 to 1.0
Al = 0.04-0.1
N = 0.02 to 0.12
And steel for cutting tools consisting of iron and impurity elements as the balance. The following concentration ranges near mass% Ru next element C = 0.93 ~1.07
Al = 0.05 to 0.07
N = 0.03-0.1
The steel according to claim 1, comprising:   The steel according to claim 1 or 2, wherein a ratio of aluminum to nitrogen (Al / N) is 0.5 to 1.9.   A circular saw for cutting metal, wherein the cutting tool is made of the steel according to one of claims 1 to 3, and has a hardness greater than 63 HRC at least in the tooth tip region.