JPS5943859A - Surface hardened cu alloy member with superior wear resistance at high temperature - Google Patents

Abstract

PURPOSE:To obtain a surface hardened Cu alloy member with improved wear resistance at high temp. by boriding the surface of a Cu alloy member contg. a specified amount of Fe and having a structure contg. dispersed relatively coarse primary crystal Fe and fine precipitated Fe. CONSTITUTION:A Cu alloy consisting of 5-50wt% Fe and the balance Cu with inevitable impurities or further contg. 0.02-1.5% Zr and 0.005-0.25% P is refined. The alloy is rolled or forged and heat treated to form a structure contg. relatively coarse primary crystal Fe and fine precipitated Fe dispersed in the matrix. The surface of the resulting Cu alloy member is borided to form a hardened surface layer. This alloy member has superior wear resistance at high temp. and superior heat conductivity, so it is suitable for use in the manufacture of a casting mold, a rolling roll, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention has excellent heat resistance and abrasion resistance, and can be used to cast mold members for continuous casting equipment such as steel, which require wear resistance especially at high temperatures, and to cast strips directly from molten metal. CU alloy members with a surface hardening layer by boriding suitable for use in the production of rolling roll members that directly receive molten metal in manufacturing equipment, ring members of electric resistance welding equipment, and electrode members for printed wiring soldering. It is related to.

Conventionally, this type of member generally has thermal conductivity.

Since heat resistance and wear resistance are required, small amounts of Cr, Ti, Be, and Zr are added to CU as alloy components.
There are also known ones made of precipitation-hardened Cu alloys, which are heat-treated and precipitation-hardened, and those made of hard Cr plating on the surface of Cu or Cu alloy members. For type CU alloy members, even the hardest Cu-Be alloy has a Vickers hardness (Hv).
: Izukizu with a degree of 300 seeds 1. j. In the latter hard Cr plated parts, the Cr plating layer may crack or peel off due to thermal stress or external stress.
The current situation is that satisfactory performance cannot be achieved over a long period of time.

Therefore, in order to obtain a member that exhibits excellent heat resistance and wear resistance (hereinafter referred to as high-temperature wear resistance) in the above-mentioned fields, the present inventors have determined that the application of Cu alloy is essential, especially from the aspect of thermal conductivity. As a result of conducting research based on this fact, it was found that these members contained Fe: 5 to 50% by weight%,
Furthermore, if necessary, one or two of Zr: 0.02 to 1.5% and P: 0.005 to 0.25%.
The composition contains seeds, and the rest is Cu and unavoidable impurities, and is heat-treated to form relatively coarse primary Fe (crystallized during the solidification process) and fine precipitated Fe (formed after heat treatment). ) is uniformly dispersed in the matrix, and in this case, the primary Fe has a Vickers hardness l1v)
:220, but it does not contribute much to the strength of the substrate, while the precipitated Fe has a Hv:1301. Although it is not shown, it is extremely useful for strengthening the base material, and when boriding is applied to the surface of a CU alloy member having such a composition and structure, B diffused from the surface mainly reacts with primary crystal Fe. In this case, the hardness of the base part where the precipitated Fe becomes borated Fe does not increase much, and H
Although it only shows a hardness of v: 200, the part where the primary crystal Fe becomes borated Fe shows extremely high hardness (v: 500 to 1100), and the resulting surface hardening CU
It was discovered that alloy members have excellent high-temperature wear resistance when combined with a high Fe content.

This invention was developed based on the above findings, and contains Fe: 5 to 50% by weight, Zr: 002 to 1.5% and P: 0.0% as necessary. 005～
025%, and the rest is Cu.
A surface hardening layer is formed by a fertilization treatment on the surface of a Cu alloy member, which has a composition consisting of 100% and unavoidable impurities, and a structure in which relatively coarse primary Fe crystals and fine precipitates) and 'e are dispersed in the matrix. It is characterized by a surface-hardened Cu alloy member that is formed with excellent high-temperature wear resistance.

Next, the reason why the composition range of the surface-hardened Cu alloy member of the present invention is limited to the range described in 1 will be explained.

(a) In FeD3E, a part of it crystallizes as relatively coarse primary Fe crystals during solidification as described above, and this primary crystal Ji'e
is borated by the boriding treatment performed in the subsequent process D' e
This increases the hardness of the material surface and improves wear resistance.
In addition to having the effect of increasing the heat resistance of parts, some other parts are precipitated as fine precipitates 11"e through heat treatment, and have the effect of improving the strength of the substrate, and further improving the heat resistance of the member. If the content is less than 5%, the crystallization of primary Fe is insufficient, and the surface hardness due to fertilization treatment is reduced.
(If primary Fe does not exist,
Since Cu does not form borides, it is impossible to significantly improve the surface roughness of the component by fertilization treatment.On the other hand, it is difficult to contain more than 50% Cu alloy. Not only is this accompanied by a decrease in ductility, which impairs workability,
+c' f5~50%.

(b) Zr The inclusion of Zr improves the ductility of the member in the temperature range of 200 to 600°C, and accordingly improves the thermal fatigue cracking resistance, so these properties are required. However, if the content is less than 0.02%, the desired effect of improving the above-mentioned properties cannot be obtained, while if the content exceeds 1.5%, the improvement will be even greater. This is not an idiot 9 where the two effects do not appear, but it becomes difficult to melt and the processability also deteriorates.
Its content was determined to be 0.02 to 0.25%.

(c) 'p In addition to suppressing the occurrence of segregation in the ingot, the P component has the following properties:
Fe, which crystallizes as primary crystals, has the effect of uniformly and finely dispersing the material, thereby inhibiting mechanical bending of the component, so it may be included as necessary when particularly high strength is required. However, if the content is less than 0.00%, the desired strength cannot be achieved, while if the content exceeds 0.25%, the thermal conductivity will decrease. The content was determined to be 0005% to 025%.

In addition, in the surface hardened Cu alloy member of the present invention, one or two types of Ca, Li, and Mg are added in an amount of 001 to 02% for the purpose of cleaning the ingot (as a deoxidizing agent). ``-'' may be included respectively.

Next, the surface-hardened Cu alloy part of the present invention will be specifically explained using examples.

Example 1 Using a high frequency induction furnace, in a graphite crucible in a vacuum atmosphere,
After preparing 5 kg of each Cu alloy molten metal having the composition shown in Table 1, it was mold-cast into an ingot, which was subjected to face milling, hot finishing, and hot rolling to obtain a plate thickness. : A 10 mm hot-rolled plate was then cut out from the hot-rolled plate with dimensions of 25 mm in width and 250 mm in length. The molten flux (composition: in weight %, F34C2 80% + H3BO3: l 0%,
After performing a boriding treatment by immersion in Na2B40□: 10%) for 6 hours, it was taken out into the atmosphere and immediately cooled with water, and finally aged at a temperature of 470°C for 2 hours. Surface hardened Cu alloy plate materials 1 to 10 of the present invention
were manufactured respectively.

Moreover, for the purpose of comparison, conventional Cu alloy sheets 1 to 4 were manufactured under the same conditions except that the composition ranges were as shown in Table 1 and the boriding treatment described in - was not performed. Additionally, for comparison purposes.

The oxygen-free copper of the conventional Cu alloy plate material 4 was hard Cr plated under normal conditions, and this was used as the conventional Cr-plated Cu alloy plate material.

Next, for the various plate materials obtained as a result, the maximum surface hardness and the minimum hardness at the center of the plate thickness (Vickers hardness) were measured, and a cantilever bending test was conducted to measure the bending angle at which surface cracking occurs. .

These measurement results are also shown in Table 1.

From the results shown in Table 1, the surface hardened Cu alloy plates 1 to 10 of the present invention all have higher surface hardness than the conventional Cu alloy plates Control to 4, and are equivalent to the conventional Cr-plated Cu alloy plates. Or it can be seen that it has a significantly high surface hardness of υl. In addition, the surface hardened Cu alloy plate material 1 of the present invention
It is clear that the surface hardened layer in No. 10 has superior adhesion and toughness compared to the Cr plating layer in the conventional Cr-plated Cu alloy plate material.

Example 2 Using a high frequency induction furnace, in a graphite crucible in a vacuum atmosphere,
After melting 250 kg of each Cυ alloy molten metal having the composition shown in Table 2, it was cast into an ingot, and this ingot was hot forged to have a cross section: ], 70
A prismatic cavity with the \" method of 鮮×length near 50mm was made, and then machining was added to this to create an upper inner diameter: 135@mX lower inner diameter: 134 striations×outer diameter: 155mm×length: 690
A tapered tubular mold with a dimension of So, B4C: 80%, H
31303: 10%, Na2B4O7: 10%)
After being subjected to boriding treatment by immersion in the air for 6 hours, it was taken out into the atmosphere and immediately cooled with water, and finally in the air at a temperature of 47
Surface-hardened Cu alloy J-shaped members 1 to 10 of the present invention were manufactured by aging at 5° C. for 2 hours.

Table 2 For the purpose of comparison, conventional Cu alloy mold members 1 to 4 were manufactured under the same conditions except that the component composition ranges were as shown in Table 2 and the above-mentioned boriding treatment was not performed. did.

Next, as a result of this, the surface of the present invention (Cu monocarbide)
Alloy mold members 1 to 10 and conventional Cu alloy mold part 1g1
A continuous casting test was conducted using 4 to 4 under the conditions of casting steel type: SUS 304 (stainless steel), casting amount per charge: 301,0 months, (upper inner diameter 135 myn
0-Lower inner diameter: 134mrX”)÷2 = 0.5
The inner taper of H77H is 0.25 rar/LK 1
! :: The number of Cianos until wear was measured. The measurement results are also shown in Table 2.

From the results shown in Table 2, the surface-hardened Cu alloy mold members 1 to 10 of the present invention all have excellent high-temperature abrasion resistance, and therefore have a significantly higher efficiency than the conventional Cu alloy nails J-shaped parts 1 to 4. It is clear that it has a long service life.

Example 3 Using a high frequency induction furnace, in a graphite crucible in a vacuum atmosphere,
After melting each 100 kg of Cu alloy molten metal having the composition shown in Table 3, it was cast into an ingot.
This ingot was hot forged into a cylindrical material with dimensions of outer diameter: 2101 fi x length: 220 mm, and from this cylindrical material outer diameter: 200 mm x wall thickness: 30 mm x length:
A sleeve material with a size of 200 m1 was cut out, and then a molten flux (composition: by weight, B, C080%, H3BO3, which had been heated and melted in a graphite crucible and maintained at 950°C) was applied to this sleeve material. : l 0%,
After being immersed in Na2B4O7 (10%) for 6 hours, taken out into the atmosphere, immediately heated and melted in advance and held at 480°C, immersed in anhydrous balmic acid, and subjected to boration treatment and aging treatment for 2 hours. Five surface-hardened CU alloy sleeve materials 1 to 3 of the present invention were manufactured by successively applying the following steps. 3. For the purpose of comparison, conventional sleeve materials were manufactured on a Cu base under the same conditions except that the composition range was as shown in Table 3 and the boriding treatment described above was not performed.

Next, the resulting surface-hardened CU alloy sleeve materials 1 to 3 of the present invention and the conventional Cu alloy sleeve materials are each made into a set of two, and a vacuum melting casting surface t') is used to directly cast and roll a metal strip from the molten metal. Used as a water-cooled roll for quench rolling of molten metal in the 2-rolling device, Charso casting and rolling amount:
1kg, Roll rotation speed: 3 Or-plm-, Product dimensions: Width 2 Omm, X plate 11. j f,] scarcity 1 m
A Tl plate was manufactured under the conditions of 10 m and 30 m.
Maximum plate thickness in the width direction of product Tl plate per charge -
In addition to measuring the minimum plate thickness (hereinafter referred to as plate thickness difference), Tl
The roughness of the plate surface was observed, and the unevenness of the roll surface was also measured for the purpose of evaluating roll deformation. The surface roughness of the Tl plate was evaluated by comparing it with the Tl plate immediately after the production started, and those equivalent to this were marked with an ○, and those with slight roughness were marked with an X. In addition, the surface roughness of the roll was actually measured using the roll surface roughness C, and the results were calculated from the maximum value to the minimum value. These results are also shown in Table 3.

As is clear from the results shown in Table 3, in all of the surface hardened Cu alloy sleeve materials 1 to 3 of the present invention,
Even after 0 charges, there is very little roll deformation and roll surface roughness, so a product Tl plate with high dimensional accuracy and a clean surface can be obtained. Since significant roll deformation and roll surface cracking had already occurred, the dimensional accuracy and surface quality of the product T1 plate were extremely poor, and it became unusable after 11 years.

]-As mentioned above, the surface hardened Co alloy member of the present invention has the following characteristics:
In particular, coarse primary F crystals are dispersed in Cu alloys.
The hardened surface layer made of Fe boride, which has extremely high hardness, provides excellent high-temperature wear resistance and excellent thermal conductivity. When used in the above-required applications, it exhibits excellent performance over an extremely long period of time.

Applicant: Mitsubishi Metals Corporation

Claims (1)

[Scope of Claims] (1) Fe: composition with a weight distribution of 5 to 50, with the remainder being Cu and unavoidable impurities, and relatively coarse primary Fe and fine precipitated Fe dispersed in the matrix. A surface-hardened Cu alloy member having excellent high-temperature wear resistance, which is obtained by forming a surface-hardening layer by fertilizing treatment on the surface of a Cu alloy member having a hardened structure. (2) Fe: Contains 5 to 50% by weight, and further contains Z
r: 0.02 to 152 to 15% by weight, the remainder being Cu and unavoidable impurities, and C having a structure in which relatively coarse primary Fe crystals and fine precipitated Fe are dispersed in the matrix.
Surface hardening C has excellent high-temperature wear resistance by forming a surface hardening layer on the surface of the u-alloy member by fertilization treatment.
u alloy member. (Contains 31Fe: 5 to 50% by weight, and further contains P: 0
005~025005~025% by weight is Cu and non-1jJ
C having a composition consisting of dirty impurities and a structure in which relatively coarse primary Fe and fine precipitated Fe are dispersed in the matrix.
Surface-hardened C with excellent high-temperature wear resistance, formed by forming a surface-hardened layer on the surface of the u-alloy part C by fertilizing treatment.
u alloy member. (4) Fe: Contains 5 to 50 g1% by weight, and further contains Zr. 002-1.5% by weight and P: 0.005-0.25:
Cu containing iI+,', fi %, with the remainder consisting of Cu and unavoidable impurities, and a structure in which relatively coarse primary Fe crystals and fine precipitated Fe are dispersed in the matrix.
A surface-hardened CLI alloy member having excellent high-temperature wear resistance, in which a surface-hardened layer is formed on the surface of the alloy part 41 by a fertilizing treatment.