JPH01502595A - Coating method for long and narrow workpieces - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Coating method for long and narrow workpieces field of invention The present invention relates to the non-a-mechanical processing of materials, and in particular to the coating of elongated workpieces. It is related to

prior art The methods of applying the coating are known (A, V, Abrasin ``Wear resistance with self-fusing hard alloys''). "Research on Strengthening Methods", Bryansky Transport Machine Research Institute, 1977, pp. 84-93) .

This known method applies Cr, B, W (chromium) to workpieces made of cast iron or rust. , boron, tungsten) and other carbides. A coating material consisting of a self-fusing alloy powder of boron-silicon is applied by flame spraying. It is implemented by using

To increase the bond strength of the coating material to the workpiece.

The melting temperature can be lowered by immersing the workpiece in a substance such as barium melt. heating to a temperature of at least 500° above the melting point of the coating material; Hold for 1 to 3 minutes at a time, then remove the workpiece from the salt bath and allow to cool.

The process of immersing the coated workpiece in a molten salt bath melts the coating and increase its density compared to the state in which it was applied and improve its degree of adhesion to the workpiece. Ru.

After cooling the workpiece to room temperature, the salt residue is removed from its surface. By coating Incomplete removal of glue on unprotected workpiece surface areas can lead to crystalline corrosion. arise.

However, when carrying out the conventional method described above: It is impossible to fix the workpiece due to the Especially for long, slender workpieces and complex It is impossible to fix the shape of the workpiece.

This results in bending of the workpiece during the heating process. On the other hand, when cooling the workpiece with air, Uneven heat loss causes workpiece bending, which is especially true for workpieces with complex shapes. It will be done.

The development of internal stresses during the manufacture and use of the workpiece also results in its deformation and bending.

Melting the coated workpiece for complete melting of the coating material a! How long to keep in the bath It is difficult to decide.

Insufficient holding time of the workpiece in the molten salt bath results in incomplete melting of the coating material. , that is, it is impossible to melt the metal body due to the thickness of the toothed metal, and the holding time is too long. tends to cause some of the molten coating material to flow.

The coating process of workpieces with complex shapes and variable cross-sections requires Involves bending of the workpiece during air cooling.

Due to the heating of the small cross-section part of the workpiece, cracks occur in the cross-sectional area of the workpiece, resulting in poor coverage. performance and result in uneven coating thickness.

During melting, parts of the workpiece not protected by the coating are exposed to the S molten salt bath. It is corroded by certain things. Removal of salt from workpiece surfaces not protected by coatings If it is incomplete, crystal mass corrosion will occur after air cooling of the workpiece.

Summary of the invention This invention is! High-quality @covering without causing deformation of rough-shaped fan-long walls. Provides a method of coating long box workpieces that can be applied.

The aforementioned goal of the invention is to apply a coating material to the surface of a workpiece and to apply the coating material until melted. In the method of coating long workpieces by heating and then cooling, before melting the ItL coating, The workpiece is placed in a refractory powder material, and the refractory powder material is compacted to form the workpiece. After fixing and melting the coating, an intervening diffusion zone is formed between the coating material and the workpiece. The workpiece is kept in the ignitable powder material until the vLvt material crystallizes. This is achieved by the method used.

By housing the workpiece in compacted scorch powder material, the workpiece can be It can be fixed reliably using an effective and inexpensive method. If the workpiece has hollow parts, protrusions or Even if the surface has a concave portion, it is faced facing 'c! Surface of artificial powder materials and workpieces 7 i: Due to the close engagement with c, in any shaped part coated with any material Reliable holding of the workpiece by the refractory powder material is ensured.

A workpiece held in this way will not bend even when heated to the melting point of its coating. Also, the internal stress generated during the manufacture and use of the workpiece is uniform throughout the workpiece. distributed and does not cause deformation of the workpiece.

By holding the workpiece at the melting point of its coating, the molten coating reacts back with the workpiece surface. to form an intervening diffusion zone.

The presence of such intervening diffusion zones ensures strong adhesion of the coating to the workpiece surface. guaranteed and due to the smooth variation of physical and mechanical properties between the coating material and the workpiece. Improved performance of the workpiece is guaranteed.

When carrying out the method of the invention, the time for holding the workpiece at the melting point of its coating is exceeded. There is no tendency for the coating to run off.

This is because the refractory powder material closely engages the workpiece coating and prevents coating flow. be. A further advantage is that the workpiece itself is subject to bending effects.

The coated workpiece is melted in a refractory powder material and then cooled until the coating material crystallizes. A coating of uniform thickness with no protrusions or pores is obtained.

After removing the workpiece from the refractory powder material along with the molten coating, it is protected by the coating. Corrosion will not occur on parts of the workpiece that are not treated.

consisting of a mixture of 60-90% by weight of powder of 0.1-0.70mm particle size and 2% by weight of , O, O, consisting of a mixture with 40-10% of powder of particle size from 1 to 0.05+++n .

If a refractory powder material having the above particle size range is used, the refractory powder material can be It is possible to compact the coated workpiece to the desired degree, which makes it possible to harden the coated workpiece during heat treatment. It can be held securely.

If particles with a particle size of 0.1 to 0.7no are present in the refractory powder material in an amount of 60% by weight or less, , it becomes difficult to uniformly deposit the refractory powder material in the volume of the container.

Conversely, if 90% by weight or more of particles in this particle size range are present.

It becomes difficult to securely hold the workpiece before the melting process.

If 60 to 90 percent of particles with a particle size of 0.1 nm or less exist, the particles will stick to each other. This tendency makes uniform compaction of the refractory powder material in the container difficult.

On the other hand, if particles with a particle size of 0.7 mm or more are present at 60 to 90 percent, the concentration of particles in the container is Unreliable workpiece holding, uneven coating thickness and excessive surface roughness and requires additional machining.

If 10% by weight or less of particles with a particle size of 0.01 to 0.050n are present in the container volume, The compaction of refractory powder materials becomes uncertain.

12111 between large particles! This is because the porosity is larger than the porosity between small-sized particles.

If 40% by weight or more of particles having a particle size of 0.0, O1 to 0.0515 m are present.

Uniform compaction of this material is difficult due to the tendency of these particles to spontaneously adhere to each other. It becomes difficult.

If 40 to 10% by weight of particles with a diameter of 0.0 and 5 nm or more is used, some of the gaps between the large particles will be Excessive porosity makes proper compaction difficult as it is not filled with small particles. Become.

If 40 to 10% by weight of particles of 0.01 am or less are used, the refractory powder material will be uniform. One particle loses its ability to be rounded by the other particles, and particles spontaneously stick to each other, and the desired particle size It becomes difficult to maintain a mixture formulation with ° This is because such small particle size This is explained by the tendency of the particles to become suspended as dust.

Preferably, silica sand, powdered chamotte and zirconium are used as refractory powder materials. Use materials from concentrated groups.

The above materials are natural products, used in large quantities in industry, cheap and expensive. It has good heat resistance.

Furthermore, these materials are suitable for repeated use. Also the free flow properties of these powders results in a high initial density in the enclosed space, which causes the workpiece to melt when melting the coating. This allows for secure retention within these materials.

Preferably, the 3 pyrophoric powder material has a density of 1.65 to 2-8 g/cm'. It can be hardened.

This density II intraperitoneal material 4! : Enme is silica sand, powdered chamotte and gil To ensure that material groups such as Conium Concentrate hold the workpiece i & week ii! It is surrounded.

As a result of the hardness φ below the density of 1.65 to 2.8 g/c m3, the machining Holding things becomes uncertain. Furthermore, the tendency of the workpiece to bend increases until the coating is melted. However, the refractory powder material also loses its ability to reliably prevent the flow of coating material.

On the other hand, compaction to a density of 2.8 g/cm3 or higher is difficult to implement, and excessive Involves energy consumption.

When using refractory powder materials other than those listed above, the preferred density range may differ. is possible.

For your information, the refractory powder material is resistant to fusing due to the action of vibration at a frequency of 6 to 8 Hz. It can be solidified.

If a refractory powder material is selected from the group n, it is suitable for vibrational action within this frequency range. It is possible to securely hold the coated workpiece by twisting and compacting.

Compaction of refractory powder materials by vibration action with frequencies below 6 Hz has low efficiency.

Compacting with frequencies above 8 Hz involves mechanical shaking inside the refractory powder material. This reduces consolidation efficiency because of the tendency for the motion to dampen. As a result, the tamping process deceleration and reduce the ability of the refractory powder material to securely hold the LaF workpiece. Ru.

As is clear from the above description, the method of forming a coating on an elongated workpiece according to the present invention can be applied in multiple ways. A high-quality coating can be formed on rough-shaped workpieces, especially workpieces with long grains. .

When carrying out the method of the invention, the workpiece is not subjected to bending deformations, which is particularly important for the grain length. This is particularly important with respect to small workpieces and wall workpieces. A coating of the required thickness is obtained, This allows for the bonding of coating material and workpiece material with only a small amount of mechanical post-treatment required. The strength is substantially equal to the breaking strength of an aluminum workpiece.

The method of the present invention can be easily carried out without the use of complex equipment and using only a few materials. I can do that.

Brief description of the drawing The following two drawings will explain in detail the embodiments of the present invention shown in the drawings. A container containing a crop and filled with a refractory powder material is shown.

BEST MODE FOR CARRYING OUT THE INVENTION A method for obtaining a coating on a long workpiece is described below. Simply referred to as ``method of the invention''. Bu.

The method of the invention is carried out as follows.

Removal of oxides from the surface of the elongated workpiece, which is to be modified, and the desired surface roughness The 5th surface is coated with the machine to improve the bonding state between the coating and the surface. Prepare accordingly.

Thereafter, the workpiece is mounted on any known rotating means (not shown) of suitable construction, and Coating 2 material of desired thickness and shape is applied to the workpiece using flame spraying method known in the industry. Apply by method.

Next, the workpiece 1 coated with this coating 2 is placed in a cup-shaped container 3 along its longitudinal direction. The machine is aligned with the axis 3a and its bottom is a certain distance from the inner surface of the bottom of the container 3. The outer surface of the object 1 is also spaced apart from the inner surface of the container 63.

The space or gap between the outer surface of the workpiece 1 and the inner surface of the wall of the container 3 is fireproof. Filled with powder material 4.

A portion of this refractory powder material is previously poured into the bottom of the container 3 to hold the workpiece 1. has been done.

This material 4 is compacted to hold the workpiece 1.

The container 3, with the workpiece 1 held therein by the material 4, can be constructed using any suitable known construction. The IE is placed in a thermal furnace (not shown). Container 3 may be heated by an induction heater or other means. It can be heated.

483. The workpiece 1 with the coating 2 and the material 4 are heated in a heating furnace with the material of the coating 2. is heated until it melts.

The workpiece 1 is heated until a promulgated diffusion area is formed between the material of the coating 2 and the workpiece 51. The coating is held at melting temperature. Retention times are determined experimentally.

The diffusion zone is formed by countercurrent diffusion or interdiffusion between the material of coating 2 and the material of workpiece 1. Intermediates made of P/P and having physical or mechanical properties intermediate to those of these materials. This intervening area, which forms a layer, ensures a high bond strength between the coating 2 and the workpiece 1, and the workpiece Produces a long service life.

After holding the container 3, workpiece and material 4 at the melting temperature, the material of the coating 2 crystallizes. Cool until cool.

In this way the shape of the coating applied to the workpiece 1 is maintained.

': 4; After cooling to room temperature, take out the workpiece 1 from the container 3, and at the same time heat the container 3. Material 4 is removed from the inside of the container by turning it over.

The workpiece 1 is then machined to the desired dimensions.

The above steps will be explained with reference to the following examples.

Example 1 The workpiece, in this case a camshaft made of high-strength cast iron, is coated as described above. Prepare the material by flame spraying and apply FIt2 of 241 alloy on the top of the column by flame spraying. .

Next, the camshaft 1 is placed in the container 3, and two portions of different particle sizes are added to the container. a mixture consisting of 60% by weight of powder with particle size 0.2 nm and particle size 0-01 40 mm of powder! Silica sand 4 is introduced as a mixture consisting of

This silica sand is reduced to 1.65g/CI! by the vibration action at a frequency of 6Hz. Firm it to a density of '.

The container 3 containing the camshaft 1 held by the compacted silica sand 4 is placed in the furnace. Place in a pot and heat until coating 2 melts.

Next, after holding the camshaft 1 at a melting temperature of 1100°C, the coating material is applied as described above. Cool until crystallized.

After cooling to room temperature, insert camshaft 1? Start from r=3.

Final a! Add machining.

Example 2 The camshaft 1 made of high-strength cast iron is then encased in a fireproof container as described above. The powdered material 4 is charged.

In this case, the silica sand contains an additive in the form of powdered chamotte and also contains two parts of different particle sizes. A mixture of minutes, i.e. 80 weight powder of 0.11 particle size? :%, 0, 03mm particle size It consists of a mixture of 20% by weight of powder. Frequency 7H for this intrusive powder material 4 Apply z vibration action and compact to a density of 1-8 g/cm'.

Covered 'F! The camshaft 1 to which i2 has been applied is heated in a furnace until the coating 2 melts. After maintaining the temperature at 100° C., it is cooled until the coating 2 crystallizes.

After cooling to room temperature, this cam r! Take out 1 from container 3 and t! A Machining .

Example 3 A cam still made of high-strength cast iron coated with Wt Fi2 is placed in a container as described above. Place it in 3.

A refractory powder material 4 is charged into the container 3, and the camshaft 1 is placed inside the container 3. Fix it. This material 4 is a zirconium concentrate with different particle sizes. A mixture of two parts, i.e. 0.7! 90% by weight of powder with ln particle size and 0.05+m 10% by weight of powder.

This zir-nium concentrate was heated to 2 ．． After compacting to a density of 8 g/cm', the material of Coating 2 is melted in a furnace. 1100℃ country @survey report

Claims (5)

[Claims] 1. The coating material (2) is applied to the surface of the workpiece (1) and heated until it melts. In the method of coating elongated workpieces in which the workpiece is cooled after coating (2), the workpiece is (1) is placed in the refractory powder material (4), and the refractory powder material (4) is placed in the refractory powder material (4). After hardening and fixing the workpiece (1) and melting the coating (2), the material of the coating (2) and Covering the workpiece (1) (2) until an intervening diffusion zone is formed between the workpiece (1) The refractory powder material (4) is cooled until the material of the coating (2) condenses. A coating method for long and narrow workpieces that is characterized by being carried out until crystallization occurs. 2. The refractory powder material is a mixture of two parts with different particle sizes, ie from 0.1 to 0. 2% by weight of powder of 7mm particle size and 0.01-0.05mm particle size Claim 1, characterized in that it is used as a mixture with 40 to 10% by weight of a powder of The method described in. 3. Refractory powder materials include silica sand, powdered chamotte, and zirconium condensate Claim 1 characterized in that the material is selected from the group consisting of Method described. 4. The refractory powder material is compacted to a density of 1.65 to 2.8 g/cm3. The method according to claim 1, characterized in that: 5. The refractory powder material is specially compacted by vibration action at a frequency of 6 to 8 Hz. 4. The method according to claim 3, wherein the method comprises: