JPS62109939A - Ni metallic material for nitriding treatment - Google Patents

Abstract

PURPOSE:To obtain an Ni metallic material for a nitriding treatment which can be improved in hardness and wear resistance by the nitriding treatment and has excellent corrosion resistance and workability by incorporating a specific compsn. ratio of Ti or Nb into metallic Ni. CONSTITUTION:0.1-15% Ti and/or 0.2-20% Nb is incorporated into the metal lic Ni. The respective lower limits are specified to 0.2% Ti and 0.5% Nb in the case of independently using Ti and Nb; further, if necessary or separately, at least one kind of 1.5-12% Cr and/or 0.3-15% Al is incorporated therein. The respective lower limits are specified to 1.0% Cr and 0.7% Al in the case of independently using Cr and Al. The Ni metallic material for the nitriding treatment is thus obtd. The above-mentioned material is made of the compsn. contg. at least 1 kind among <=20wt% Fe, <=5% Si, <=20% Mn, <=10% Mo, <=20% Cu, and <=20% Co and consisting of the balance Ni and inevitable impuri ties, by which the various characteristics of the base metal of the metallic Ni are strengthened.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an Nl metal material for nitriding, particularly to a Ni metal material for nitriding to which a nitride-forming element is monopolarly added.

(Prior Art) Conventionally, various mechanical parts and tools have often been required to have hardness and wear resistance, and research on materials has been conducted to meet these requirements. However, materials that are hard and have good wear resistance are generally difficult to process, so research is also being conducted into applying surface hardening treatment after processing. For example, mechanical parts with improved wear resistance are made by forming special steel called nitriding steel into a predetermined shape and then subjecting it to nitriding to harden the surface. It is also known that nitriding stainless steel significantly hardens its surface.

These are Cr contained in nitriding steel and stainless steel.
This is because Al and Al become nitrides through nitriding treatment, forming a hard nitride layer on the surface layer. However, in the case of alloys whose main component is iron, such as nitriding steel and stainless steel, Cr in the alloy becomes nitrides and is lost, resulting in a significant decrease in the Cr concentration in the base metal directly below the nitride layer. As a result, corrosion resistance deteriorates and iron rust is more likely to occur.

Note that nitriding steel and stainless steel SVt, especially stainless steel, are difficult to form, so their use as mechanical parts may be limited depending on their shape.

By the way, metal nickel has much better corrosion resistance than iron, and hardly corrodes in the atmosphere, fresh water, and seawater. In addition, it has relatively good workability and can be easily processed into shapes such as plates, rods, and wires. However, since metallic nickel itself is extremely difficult to nitride, it is said that it is impossible to form a nitride layer on its surface using normal methods.

On the other hand, among the above-mentioned nitriding steels and stainless steels, stainless steel in particular does not have sufficient formability, and the corrosion resistance of nitrided steels or stainless steels deteriorates, as the environments in which they are used are becoming increasingly corrosive. , has become a big problem.

(Problem to be solved by the invention) Thus, not only its excellent workability, but also...1
The inherent corrosion resistance of the gold luster material was noticed,
As such, excellent corrosion resistance and surface abrasion resistance are now required, and a material that satisfies these requirements is desired.

Therefore, it is an object of the present invention to provide a metal material having low corrosion resistance that can be nitrided.

(Means for solving the problem) In order to solve this problem, the inventors of the present invention have conducted various studies and found that Ti, Nb, and even Ni metal have been added to other alloy elements. , or No. 1 Noko Cr
The present invention was completed based on the discovery that a Ni metal material obtained by adding Al to Ni metal has excellent corrosion resistance and is easily surface hardened by nitriding treatment.

Here, the gist of the present invention is: Roha, fffffl
%, Ti:O, 1-15% and/or ', (b: 0.2
~20%, depending on need, or another 2%, Cr
: 0.5-12% and/or Al: 0.3-15
%, but if only one of them is included, the lower limits are Ti: 0.2% and Nb: 0.5%.
, Cr: 1.09'o, and Al: 0.7%.

That is, in other words, according to the gist of the present invention, Ti:0.
1-15% and/or Nb: 0.2-20%,
Furthermore, if necessary or separately, Cr: 0.5~
This is a method of nitriding gold BNi characterized by adding 12% and/or 0.3 to 15% Al.

According to a preferred embodiment of the present invention, the Nl metal material has a weight percentage of 2
0% or less Fe, 5% or less Si, 20% or less Mn
, 10% or less Mo, 20% or less Cu, and 20%
It may be a Ni metal material for nitriding treatment containing at least one of the following Co, with the remainder being Ni and unavoidable impurities.

Furthermore, in another preferred embodiment of the present invention, T1, Nb,
The total addition F4 of Cr and Al is the resultant Ni alloy +
Considering the processability of material A, it is preferable to add Ir11 to 10% or less.

In addition, in order to improve the characteristics of the base material mentioned above, Fe and M were added to the metal Ni.
When adding n, Mo, Cu, Si, Co, etc., the total amount added is preferably 15% or less.

Therefore, according to the present invention, unlike conventional nitrided steel and stainless steel, it is possible to improve the hardness and wear resistance by nitriding treatment without impairing the corrosion resistance and other properties inherent in metal Ni. It was. Moreover, it has been found that Ti and Nb are more effective elements for forming nitride layers than just A1 and Cr, which were conventionally thought of in Fe-based alloys.This makes the nitriding treatment of Ni metal materials even more effective. This means that it will be carried out on a regular basis.

(Function) Next, the reason why the alloy composition is limited as described above in the present invention will be explained in detail below.

Note that Ti, Nb, Cr, and Al are all nitride-forming elements, and to that extent they are equivalent, but
Since there are some differences in the amount added and the action as a nitride, the action and effect of each common type will be explained. In particular, the addition of Ti and/or Nb significantly improves its nitriding ability.

Ti: Ti is an element that makes Ni metal materials extremely susceptible to nitridation. The larger the amount added, the greater the effect, but if it exceeds 15%, the workability of the alloy will deteriorate significantly. Preferably it is 10% or less. When added alone, less than 0.2% has no effect. When added in combination with other nitride-forming elements, it is preferable to add 0.1% or more.

Nb: The effect of nitriding Nb is not as great as that of Ti, but when added alone, the effect is seen at 0.5% or more, while at 20%
If the temperature is too high, the workability will deteriorate significantly. It is preferably 15% or less.

When added in combination with other nitride-forming elements, the amount is 0.2% or more.

Al: When Al is added alone, it requires an addition of 0.7% or more, but when added in combination, it is 0.3% or more.

On the other hand, if it exceeds 15%, workability deteriorates significantly. It is preferably 10% or less.

Cr: When Cr is added alone, its effect is not recognized if it is less than 1.0%, and it is necessary to add 1.0% or more. In that case,
Forms a clear nitride layer on the surface and hardens the surface. However, since nitride layers made of Cr tend to be thinner and more brittle than those made with additions such as Ti,
It is preferable to increase the addition ratio of other Ti, Nb, Al, etc. for curing. The lower limit for compound addition is 0.5%
It is.

Here, the Ni metal material referred to in the present invention may be made by adding the above-mentioned nitride-forming elements to pure Ni, and may further include Fe, Si, Mn, Cu, Mo to improve the parent material properties.
, and those containing at least one type of Co are also included. In the present invention, since the amount of these additive elements is limited, high N
It is well distinguished from i-based alloys. However, it is understood that the Ni metal materials referred to in the present invention also include materials that produce generally-called Ni alloys by adding the above-mentioned additive elements, including nitride-forming elements. Should.

Typical Ni metal materials in the present invention include those containing at least one of the above alloying elements within the following ranges.

Fe: 20.0% or less, Si: 5.0% or less, Mn: 20.0% or less, Mo: 10.0%
Below, Cu: 20.0% or less, Co: 20.
Less than 0%.

The reason why the above-mentioned composition is preferred as the Ni metal material in the present invention is as follows.

Fe: Contribution to hardness increase due to nitriding is small, and although it is not necessarily necessary in the present invention, Fe is added to reduce material cost.
It may be added in an amount of 0% or less.

Si: Although its contribution to the increase in hardness due to nitriding is small, it is effective as a deoxidizing agent during alloy production, so addition of up to 5.0% is permitted. If it exceeds 5.0%, it causes deterioration in workability.

Gate n, Cu: These have a small contribution to the upper bound of hardness due to nitriding, but
In order to reduce material costs, addition of 20.0% or less is allowed. Addition of more than 20.0% causes deterioration of workability and corrosion resistance.

0: Although the effect of increasing hardness due to nitriding is small, it may be added in an amount of 10.0% or less for the purpose of improving corrosion resistance. However, if it exceeds 10%, it causes deterioration in workability.

CO: Although the effect of increasing hardness due to nitriding is small, it may be added as a substitute element for Ni in an amount of 20.0% or less. However, pressing it causes deterioration in workability.

8. Unavoidable impurities include cases where trace amounts of Si and Si added to prevent the formation of pores (blowholes) in the ingot remain in the form of nonmetallic inclusions such as oxides, and cases where raw materials -
Impurity elements contained in furnace materials (e.g. P, S, C)
) may be mixed in.

In the present invention, the term "for nitriding" means that the surface is easily nitrided by nitriding, and not only is the surface nitrided and hardened, but also that nitrogen diffuses from the surface to the inside. This also includes an increase in the hardness and strength of the material as a result. Further, in the embodiments of the present invention shown below, only the ion nitriding method is disclosed as a nitriding method, but the alloy for nitriding according to the present invention can also be processed by a conventional gas nitriding method or a salt bath nitriding method. Needless to say, it has the property of being easily nitrided.

This is because the nitriding reaction is a reaction between alloy components and nitrogen, and the rate of nitrogen diffusion into the alloy is also specific to that alloy, so the ease with which it is nitrided depends mostly on the properties of the alloy. It is from.

In addition, the Ni metal material according to the present invention has good workability and can be processed into the shape of a plate, rod, or wire.
The present invention is not limited by the form.

Next, the present invention will be explained in further detail with reference to Examples.

An alloy having the composition shown in Table 1 was melted using the high-frequency induction vacuum melting method, and after it was forged to a thickness of 10no++,
It was heat treated at 900°C for 15 minutes and air cooled. 2t from this
A test piece of x 10 x 20 mm was cut out and ion nitrided at a treatment temperature of 600° C. for 3 hours in a mixed gas atmosphere of nitrogen and hydrogen (nitrogen 50 νo1.%) at a pressure of 6 Torr. Table 1 also shows the results of determining the surface hardness after ion nitriding using a MicroVinocurs hardness meter.

Ti as a nitride-forming element? E and/or Nb,
Inventive material 1 further added with Cr and/or i:
l-I C% 1-16) is pure ~i or this with Fe, Mo
, the surface hardness is greater than that of the comparative samples containing Si (Okina (Arashi 17-21)).Surface hardness increases almost in proportion to the amount of added elements, but the degree varies greatly depending on the element. This is clear from the test results in Table 1, and if these relationships are generally shown in a graph, it will look like the attached drawing.In other words, Ti has the greatest effect, Nb has the least effect, and this is This was not known even for nitrided steel and stainless steel S4, and then even for A1.
The hardening ability decreases in the order of Cr. On the other hand, Si,
'+M -'h for the hardness upper bound of Mo, re!
,'? Small - < , , + h, ; No rr -D (F) j'F: 1111 G
7F-tm + and "J-" are not very effective in increasing hardness.

Next, Table 1 also shows the presence or absence and thickness of the nitrided layer. According to this, T1 has a strong effect of thickening the nitrided layer, and Al causes a considerable increase in hardness without forming a clear nitrided layer. On the other hand, when Cr is added, a clear nitrided layer tends to be formed, but the formed nitrided layer is relatively easy to separate from the base metal. From this point of view, it is effective to limit the amount of Cr added and increase Ti or A1 in order to prevent peeling of the nitride layer.

Furthermore, Table 1 also shows the degree of edge cracking that occurred in the test pieces due to forging. All of the materials of the present invention have good workability, but the materials from floor 22 to
Comparative material No. 25 had significant cracking due to forging, and a test piece for ion nitriding could not be made.

(Effects of the Invention) As is clear from the above explanation, the present invention is applicable. (1) Metallic materials have the property of being very easily nitrided, and at the same time have excellent workability and corrosion resistance, and have the potential to be used not only for various mechanical parts and tools, but also for a variety of other uses.

[Brief explanation of drawings]

The accompanying drawings are graphs summarizing data of embodiments of the present invention. Applicant Hiki Stainless Co., Ltd. Agent Patent Attorney Akira Hirose - OS IQ 15 20 25 30+Kurayt-
Kaiban qicwt fake)

Claims (6)

[Claims] (1) Ti: 0.1 to 15% and/or N to metallic nickel in weight%
b: 0.2 to 20%; however, if only one of these is included, the lower limit is Ti: 0.2%.
and Nb: 0.5%, a Ni metal material for nitriding treatment. (2) The Ni metal material contains 20% or less F by weight%
e, 5% or less Si, 20% or less Mn, 10% or less Mo, 20% or less Cu, and at least one of 20% or less Co, with the balance being Ni and unavoidable impurities. Ni metal material for nitriding treatment according to scope 1. (3) Cr: 0.5 to 12% and/or A to metallic nickel in weight%
Nitriding treatment in which at least one of l:0.3 to 15% is contained; however, when only one of these is contained, the lower limits are Cr: 1.0% and Al: 0.7%. Ni metal material for use. (4) The Ni metal material contains 20% or less F by weight%.
e, 5% or less Si, 20% or less Mn, 10% or less Mo, 20% or less Cu, and at least one of 20% or less Co, with the balance being Ni and unavoidable impurities. Ni metal material for nitriding treatment according to scope 3. (5) Ti: 0.1 to 15% and/or N to metallic nickel in weight%
b: 0.2-20%, Cr: 0.5-12% and/or Al: 0.3-1
Ni metal material for nitriding treatment containing 5%. (6) The Ni metal material contains 20% or less F by weight%.
e, 5% or less Si, 20% or less Mn, 10% or less Mo, 20% or less Cu, and at least one of 20% or less Co, with the balance being Ni and unavoidable impurities. Ni metal material for nitriding treatment according to scope 5.