JPH01156445A - Cutting tool - Google Patents

Abstract

PURPOSE:To obtain an Ni-base alloy for cutting tools excellent in corrosion resistance and workability and having high hardness by adding specific amounts of Cr and Al to Ni. CONSTITUTION:Cr (25-50% by weight, preferably 30-45%) and 1.5-9%, preferably 2.5-6.0%, Al are added to Ni to undergo alloying. This Ni-base alloy is heated, e.g., at about 120 deg.C for 1-3hr and water-cooled to undergo solution part treatment. Subsequently, the above alloy is worked into the desired cutting- tool shape by means of a pressing machine, a cutting machine, etc. By this method, a cutting-tool stock excellent in workability and hardness which are essentially conflicting with each other and also in corrosion resistance can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a cutting tool that is easy to process, has high hardness, and is hard to cause damage to the blade during use.

(Prior art) Conventionally, cutting tools include small nail clippers, knives,
There are a wide variety of tools, including blades such as scissors and knives, hand tools such as saws and axes, and blades for meat and bread slicers, lawn mowers, and chainsaws.

The materials for these cutting tools are generally highly edible;
5US30 because it is easy to process and easy to obtain.
Stainless steel such as No. 4 is often used.

(Problem to be solved by the invention) However, although stainless steel can be said to be of good quality in terms of corrosion resistance and workability, its hardness is not necessarily sufficient when used as a cutting tool. Use causes problems such as various scratches on the cutting surface and wear of the blades involved in cutting.

In particular, stainless steel is often used for kitchen knives and knives because it does not show rust and has a beautiful appearance, so scratches on the blade will stimulate demand for functionality as well. It is also unfavorable in this respect.

Thus, although stainless steel is a material with good workability, it does not necessarily have high hardness and cannot be said to be suitable as a material for cutting tools.

It is an object of the present invention to solve the above-mentioned problems and provide a cutting tool that has excellent corrosion resistance and workability, and has high hardness.

[Structure of the Invention] (Means for Solving the Problems) The inventors of the present invention have conducted intensive studies to solve the problems related to the conflicting demands of excellent workability and high hardness, and have found the following. It was discovered that a Ni-based alloy having the following composition is suitable, and the cutting tool of the present invention was developed.

That is, the cutting tool of the present invention contains 25 to 50% by weight of chromium.
, an alloy consisting of 1.5 to 9% by weight of aluminum and the remainder substantially nickel.

In the alloy used in the cutting tool of the present invention, Ni provides toughness and corrosion resistance. Further, Cr is a component that imparts excellent corrosion resistance and is thought to promote the precipitation of α phase through grain boundary reactions, thus improving the properties of the cutting tool.

If the Cr content is less than 25%, the effect will not be fully expressed,
Furthermore, if the content exceeds 50%, the ductility may decrease and the steel may become brittle. Preferably it is 30 to 45% by weight.

AM is a component that promotes composite precipitation in correlation with other components and improves age hardenability, but if it is less than 1.5%, sufficient composite precipitation will not occur during heat treatment and the required hardness will not be obtained. If it exceeds 9%, cold workability and cutting workability deteriorate. Preferably 2.5~
It is 6.0% by weight.

The cutting tool of the present invention made of an alloy having the above composition can be manufactured as follows. That is, first, an alloy having the above composition is heated at a temperature of about 1200° C. for 1 to 3 hours and then cooled with water to undergo a solution treatment. Through this treatment, the alloy becomes a material with excellent workability of about Hv 150.

Next, it is processed using a press machine, a cutting machine, etc. to match the shape of the intended cutting tool.

After this processing, the material is subjected to an aging treatment. Conditions for the aging treatment are appropriately selected depending on the desired hardness, but are usually at a temperature of 600 to 650° C. for 5 to 7 hours.

As a result, sufficient hardness is imparted to the cutting tool.For example, when the aging conditions are 650°C for 5 hours, the hardness of the material is approximately v680. If necessary, the solution treatment may be performed again under the above-mentioned conditions prior to the aging treatment.

Next, the material subjected to the above-mentioned aging treatment is subjected to final polishing to form a cutting tool as a product.

(Example) Example 1 An alloy member having the composition shown in the table was subjected to solution treatment at a temperature of approximately 1200°C for 60 minutes, then rough-processed by cutting, and then treated at a temperature of approximately 650°C for 5 hours. After undergoing age hardening treatment, the blade was finished and polished.

Each of these blades was soaked in 5% hydrochloric acid (HC) by weight for 2 hours.
10% sulfuric acid (H2SO4) for 24 hours, 30% nitric acid (H2SO4)
A corrosion test was conducted when immersed in NO3) for 96 hours,
The results are shown in the table with the degree of corrosion at that time being defined as the corrosion rate V. Note that the corrosion rate V is expressed by the following formula.

W s −W f −T where v (g/m'φHr): Corrosion rate Ws (g)
: Weight before corrosion test Wf (g) :
tt After weight A (rn') : Total surface area of the test piece T (Hr) : Test piece immersion time In addition, the hardness (Hv) of the material when subjected to the solution treatment, which is an index of workability, and the resistance to scratches. Hardness (Hv) of the blade as a product hardened by aging treatment as an indicator
The measured values were also listed in the table.

Comparative Example 1 A sword blade was produced in the same manner as in the previous example from an ingot of the indicated alloy having a composition different from that of the alloy of the present invention.

Regarding each of these blades, the same corrosion rate (g/m''・Hr) with an aqueous solution of the above components as in Example 1, the hardness (Hv) when solution treatment was performed, and the hardness of the blade hardened by aging treatment. The hardness (Hv) of each was measured.The results are shown in the same table.

Reference example 1.2 105 in each ingot of SUS304 and 5US316
A blade similar to that in Example 1 was manufactured by solution treatment at 0° C. for 60 minutes, pressing and rough processing, and final polishing.

Each of these blades was subjected to a corrosion test using the aqueous solution used in the above example, and the corrosion rate (g/rn'・H
r), the hardness (Hv) during solution treatment, and the hardness (Hv) of the blade as a product were measured. The results are also shown in the same table.

[Effects of the Invention] As is clear from the above description, the cutting tool of the present invention not only has excellent corrosion resistance and workability, but also has sufficient hardness, so that the cutting tool has excellent hardness. It is scratch resistant and resistant to abrasion, making it of great industrial value.

Claims (1)

[Claims] 1. Chromium 25-50% by weight, aluminum 1.5-9
A cutting tool characterized in that it consists of an alloy in which the remainder by weight is essentially nickel. 2. Alloy is 30-45% by weight of chromium, aluminum 2.
The cutting tool according to claim 1, wherein the cutting tool is 5 to 6.0% by weight, the balance being substantially nickel.