JPS59197573A - Coating pretreatment in-furnace soldering - Google Patents

Abstract

PURPOSE:To efficiently and rationally perform the titled treatment in a min. process and low equipment cost, by a method wherein an alloyed steel material soldered in a furnace under a high temp. heating condition is cooled in the furnace while the cooled soldered material is immersed in a chemical forming treatment tank based on MnP to perform heat treatment and, at the same time, chemical forming coating treatment. CONSTITUTION:In a soldering furnace 1 equipped with a work charging chamber 2, a preheating furnace 3, a heating furnace 4 and a furnace cooling chamber 5, work made of an alloyed steel material preheated in the furnace 3 is heated to 800-1,200 deg.C in the furnace 4 to perform furnce soldering. Subsequently, the soldered work is cooled to about 400-560 deg.C in the chamber 5 having a cooling pipe 502 arranged thereto and the cooled work is immersed in the chemical forming treatment bath 701 based on MnP in a chemical forming treatment tank 7 where the heat treatment and chemical forming coating treatment of the work are simultaneously performed. Succeedingly, the work is sent into a coating apparatus. In this case, the bath 701 is held to about 90-98 deg.C by the holding heat of the work other than the initial heating time.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to alloy steels (for example, M n 0.7 to 20, C0
, 02-05, the remainder relates to a method for pre-painting treatment in furnace brazing of alloy steel consisting of F''e.

Furnace brazing of this combined alloy steel material is performed by heating the steel material to 800℃ in the furnace.
It may be possible to braze the steel by heating it to ~1200°C, and then leave it to cool down to room temperature in a furnace, but such conventional brazing treatment is more difficult than the steel material before heat treatment, that is, the raw material. It had the disadvantage that its tensile strength etc. deteriorated.

Therefore, in order to improve the above-mentioned drawbacks, the present applicant has developed a method of improving tensile strength, etc. by furnace cooling the alloy steel material after brazing heat to about 00°C to 560°C, and then rapidly cooling it from this temperature range. Japanese Patent Application No. 55-26597 (% 1986-12) describes a heat treatment method for alloy steel materials, which
No. 3322).

When painting the above brazing heat treated alloy steel materials,
Conventionally, workpiece surfaces were degreased, cleaned, and chemically treated (from 40°C to
After undergoing pre-treatment processes such as cleaning and drying (liquid temperature: 80°C), it is transported to the painting room. In this way, the pre-painting treatment process requires many steps, and each step requires a lot of equipment.
Equipment is also becoming more expensive, so it is necessary to reduce processes, reduce equipment, improve efficiency, rationalize, etc.
It is an object of the present invention to provide a coating pretreatment method for furnace brazing that is advantageous in terms of cost reduction, improvement in mass productivity, line consistency, and energy saving.

In order to achieve the above object, the present invention aims at a temperature of about 800°C to 1.5°C.
The alloy steel material heated to 200°C and brazed in a furnace is cooled down to approximately 400'C to 560'C by furnace cooling, and then immersed in a chemical conversion treatment tank mainly composed of MnP, and is subjected to chemical conversion coating treatment at the same time as heat treatment. The gist is that it has been implemented.

Next, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

The alloy steel used in carrying out the present invention is, for example, MnO,'
7 to 2.0%, CO 0.02 to 0.5%, and the balance FeO, and the alloy steel material to be bent is brazed in a furnace.

In brazing, a brazing material such as copper brazing or silver brazing material is interposed in the joint of steel materials in the form of a paint, and this is placed in a heating furnace to a temperature of 800°C to 120°C depending on the brazing material in a non-oxidizing atmosphere gas. Heat to melt the brazing material and print it out.

A workpiece that has been subjected to brazing heat treatment at 800°C to 120°C is cooled to 400°C to 560°C by forced cooling using a water jacket or a fan to forcefully feed a modified gas such as ammonia gas or propane. The workpiece is charged into a chemical conversion treatment tank directly connected downstream, and a treatment liquid mainly containing MnP is used to generate a chemical conversion film at the same time as heat treatment of the brazed workpiece by injection into the chemical conversion treatment liquid and immersion. The chemical conversion treatment liquid has a temperature of 90% in its initial state.
If the temperature is maintained at a temperature of .degree. C. to 98.degree. C., the processing liquid will be kept warm by the heat retained by the workpiece, and a liquid heating device will not be required.

In this way, chemical conversion coating treatment is performed as a pre-painting treatment at the same time as heat treatment, and when the chemical conversion coating treated workpiece is transferred to the painting process, the moisture on the workpiece blush evaporates due to latent heat, and the workpiece is painted as is without the need for a drying process etc. It can be performed.

By the way, the workpiece is heated to 800℃ due to furnace brazing.
The workpiece is heated to ~1200°C, and this heating burns off deposits such as oils and fats on the surface of the workpiece.The surface of the workpiece is purified in the waxing process, and the degreasing process is omitted and the workpiece is immediately cooled in the furnace, heat treated, and chemically coated. Be able to process it.

Next, a specific apparatus for carrying out the above method will be explained with reference to the accompanying drawings.

The furnace 1 includes, from upstream, a workpiece input chamber 2, a preheating furnace 3 continuous to this, a heating furnace 4 continuous to this, and a furnace cooling chamber 5 continuous to this. A conveyor 6 is provided that communicates each of these areas, and the conveyor 6 has driving wheels 601 and guide wheels 6.
An endless conveyor driven by 02... etc. is adopted.

The workpiece input chamber 2 is equipped with a shutter 202 downstream of the inlet section 201 to separate the downstream waiting chamber 203 from the outside, and is equipped with an exhaust section 204 for discharging waste heat gas from the inlet section 201 to the outside. A workpiece is put into the front upstream part of the conveyor 6, and the workpiece is conveyed to the waiting room 203. Waiting room 2
A shutter 205 is provided between 03 and the upstream part of the preheating furnace 3, heaters 302 are buried in the ceiling and floor of the furnace body 301 of the preheating furnace 3, and ammonia is installed in the ceiling of the furnace 3. Conduit 3 for introducing metamorphosed gas such as gas and propane into the interior
03 and maintain the inside of the furnace in a non-oxidizing atmosphere. The shutter 205 is opened, the conveyor 6 sends the work from the waiting chamber 203 into the furnace, and the work is preheated in the furnace 3. Furnace 3
The furnace body 401 of the heating furnace 4 adjacent to the heating furnace 4 has heaters 402 embedded in the ceiling and floor, and the above-mentioned gas is introduced into the furnace through a conduit 403 in the ceiling. The workpiece preheated in the preheating furnace is transferred to the heating furnace 4, where the temperature is 800°C to 120°C.
Heat to 0°C and perform furnace brazing. .

Cooling pipes 502 are installed on the ceiling of the furnace body 501 of the furnace cold chamber 5 provided adjacent to the heating furnace 4, and the brazed workpieces sent from the heating furnace 4 by the conveyor 6 are cooled. At this point, the workpiece is forcibly cooled by supplying atmospheric gas using a cooling fan, and the workpiece is cooled to 400°C to 560°C.
The temperature will drop to A shutter 50 is provided at the downstream part of the furnace cold chamber 5.
Equipped with 3.

A discharge chamber 504 facing the most downstream part of the conveyor 6 is defined on the downstream side of the furnace cold chamber 5 divided by the shutter 503, and the discharge chamber 504 has an exhaust gas discharge section 505 on the ceiling and is erected. The chemical conversion treatment tank 7 divided by the partition wall 506 is connected to the discharge chamber 504.
Install it directly connected to. A part of the ceiling of the discharge chamber 504 is extended downward diagonally to the downstream side to form an extension 507 of the chemical conversion treatment stored in the tank 7]I! The lower end of the liquid 701 is inserted into the tank, and a guide plate 702 is provided on the upstream side of the tank 7.
A conveyor 703 is installed downstream from below, with an upstream portion 704 facing into the liquid 701, and a downstream portion 706 facing the outside via a tilting barrel intermediate portion 705.

In the following, the workpiece is subjected to a waxing process in the heating furnace 4 in which oils and fats on the surface are burned off, the surface is purified, and the temperature is lowered to 400°C to 560°C in the furnace cooling chamber 5. In this state, the workpiece is transferred to the processing tank 7. The workpieces are continuously and directly charged, a chemical conversion film is formed at the same time as the heat treatment, and the processed workpieces are carried out by a conveyor 703.

The transported workpiece can be dried by evaporating moisture using latent heat, and sent directly to the painting process. Furnace brazing heat treatment and painting pretreatment can be performed in a continuous series of processes.

In this embodiment, the painting process is directly connected to the above-mentioned waxes, and the downstream part 706 of the conveyor 703 is introduced into the draining and drying chamber 801 of the painting device 8, and the workpieces that are pulled out from the treatment tank 7 and transported are transported. is introduced into the chamber 801, where it is drained and dried using latent heat. In the embodiment, the upstream part of the pipe 9 is connected to the discharge part 505 provided on the ceiling of the discharge chamber 504, and the combustion device 902 is connected to the upstream part 901. The first branch pipe 904 of the main pipe 903 of the pipe 9 is connected to the draining and drying chamber 801 through the valve 905, and the gas is introduced into the chamber 801 to improve the efficiency of draining and drying. planned. Incidentally, a workpiece inspection is also performed in the chamber 801.

Adjacent to the draining and drying room 801, there is a work hanging room 802 downstream.
A painting room 803 is provided downstream of this, a setting room 804 is provided downstream of this, and a baking furnace 805 is provided successively downstream of this, a hanging conveyor 806 is introduced from above the hanging chamber 80.2, and the conveyor 806 is each room 802.803.

The work passes under the ceilings of 804 and 805, is led out from the furnace 805, is transferred from the conveyor 703 to the conveyor 806, is sent to the coating room 803, and is subjected to powder coating, etc. After painting, the workpiece is transferred to a setting chamber 804 and held there, and then sent to a baking furnace 805 for baking. branch pipe 906.
908 is connected, exhaust gas is introduced into the interior through valves 907 and 909, and is carried out of the furnace after baking.

As described above, heat treatment, pre-painting treatment, and painting can be performed in a continuous manner, and exhaust gas can be used as part of the heat source during painting, which is also advantageous in terms of energy saving.

As is clear from the above (according to the present invention, heat treatment and pre-painting treatment are performed continuously using the heat retained after brazing in the furnace, and the heat treatment and pre-painting treatment can be performed simultaneously in one treatment tank. The equipment also eliminates the need for separate meals, and is efficient as it runs continuously.
In addition to being able to perform a rational integrated treatment, heat treatment is also performed in the chemical conversion treatment tank used for pre-painting treatment, so there is no need to heat or maintain the liquid temperature, and in this respect, heating equipment can be omitted, which is advantageous in terms of equipment and energy saving. It has many advantages.

[Brief explanation of the drawing]

The drawing is an explanatory view showing an example of an equipment for carrying out the present invention. In the drawing, 1 is a wax chamber, 4 is a heating furnace, 5 is a furnace cold room, and 7 is a chemical conversion treatment tank.

Claims (1)

[Claims] After heating the alloy steel material to approximately 800°C to 1200°C and brazing it in a furnace, the temperature is lowered to approximately 400°C to 560°C by furnace cooling, and then it is immersed in a chemical conversion treatment bath mainly composed of MnP, and a chemical conversion coating is applied at the same time as the heat treatment. 1. A pre-painting treatment method for furnace brazing, characterized by applying a treatment.