KR920004014B1 - Boronising pastes and boronising treatment method of ferrous and ferrous-alloy surfaces - Google Patents

Abstract

A boronizing agent for iron alloy consists of at least one of 5-60 wt.% B4C, 5-80 wt.% KBF4, 5-40 wt.% SiC and at least 50 wt.% B2O2, and one of accelerating agent and binding agent of at most 30 wt.%. The accelerating agent can be NaCl or Na2CO3 and the binding agent be at least one of alcohol, silicone binder and fluoro binder. A boronizing treatment method of iron and iron alloy surface is characterized by spreading paste of above composition on selected area of substance being boronizing treated and heat-treating it at temperature ranges of 600-1000 deg.C for 1- 10 hrs.

Description

Boronizing agent and boron penetrating surface treatment method of iron or iron alloy surface

The present invention improves abrasion resistance, heat resistance and corrosion resistance by diffusing and injecting boron (B) into the surface of a treatment agent made of iron or iron alloy, and in particular, a boronized surface treatment agent capable of selectively forming a boron layer only on a required portion; It relates to a boronized surface treatment method. Various metal surface hardening methods are known. For example, there are carburization, nitriding, carburization, and boronation. Among the boronization methods, there are molten salt method, electrolytic method, gas method and powder method. The molten salt and electrolytic method is to deposit the treated material in the molten borax to obtain a uniform boron layer and to increase the formation speed, but because it is difficult to process at low temperatures, a container having excellent heat resistance is required. An apparatus is necessary, and boron adheres to the surface of the workpiece, which requires great effort to remove it. In the gas method, boron should be gasified and treated in its atmosphere, such as chlorine gas or hydrogen gas, so that there is no deposit on the surface of the material to be treated, but the device is complicated and has low workability. The powder method embeds the target material in a mixed powder bath of boron carbide using boron carbide (B ₄ C) and ammonium chloride (NH ₄ Cl) or sodium cyanate (NaOCN) as a feed material for boron, thereby providing a specific atmosphere of hydrogen or nitrogen. the method using a mixed powder of a method of heat treatment and the boron carbide and sodium carbonate (Na ₂ CO ₃₎ or potassium carbonate (K ₂ C0 ₃₎ it is known from.

However, in such a method, sodium cyanate is a solution phase, difficult to attach to the material to be treated, and toxic due to decomposition, which is not easy to handle, and these methods are sealed to prevent the formation of iron oxide on the surface of the material to be treated. In addition to the need for processing in containers or special atmospheres such as hydrogen and nitrogen, there is a problem in that a hardened layer is formed even when the boron infiltration process is only performed at a partial position. Therefore, copper (CU) plating or chemicals are coated on unnecessary parts. Unnecessary processes that need to be added add to the cost of production.

In addition, the method of embedding the material to be treated has a disadvantage in that when the structure is large or complex, the treatment is difficult or the consumption of the treatment agent is increased. Therefore, the present invention can selectively treat only the desired portion of the material to be treated in the past in the form of a paste and can be cured even in a general heat treatment that does not require a specific atmosphere, and exhibits surface hardness (HV) of 1200 to 2000. It is an object of the present invention to provide a treatment method for diffusing and infiltrating boron to the surface of a treatment target using such a treatment while at the same time providing a technique for a surface treatment composition. Another object is to enable pollution-free treatment by eliminating the problem of wastewater treatment caused by the use of electrolytes.

Hereinafter, the present invention will be described in detail. The present invention is boron carbide (B ₄ , C) powder 5-60% by weight, carbon fluoride (KBF ₄ ) powder 5-80% by weight, silicon carbide (SiC) powder 5-40% by weight and boron oxide (B ₂ 0 ₃ ) Selected or mixed from 50% by weight or less of powder, and selected from 30% by weight or selected from accelerator and pressure-sensitive adhesive, and the composition is selected only in the part requiring boron infiltration treatment, which is plotted on the surface of iron or iron alloy. It is composed of a boron permeation surface treatment method in which boron is infiltrated by heat treatment at 650-1000 ° C. for 1-10 hours after coating. The following describes the reason for the numerical limitation and the effect ratio according to the above configuration.

In the present invention, boron carbide powder as a boron penetrating element is generally widely used, and the reason for its use is also phased out, which will be omitted.

In the present invention, the boron carbide powder is used, but the composition is composed of various composition ratios by each composition ratio is made to each other organic relationship. Carbofluoride powder is added to the boron carbide powder as an activator. If the amount is less than 5% by weight, the boron fluoride powder is less effective as an activator, or corrosion occurs on the surface. Peeling phenomenon may occur and the treatment agent becomes liquid during the heat treatment to solidify after treatment or strongly adhere to the surface of the workpiece. Silicon carbide powder is intended to diffuse and penetrate boron in the carbofluoride powder to the surface of iron or iron alloy by silicon carbide motion. Form phosphorus boron; In addition, silicon carbide is a high melting point inert powder which is added to prevent the treating agent from melting during or after heating.

Therefore, the effect is halved if it is 5% or less or 40% or more. Boron oxide becomes heavy during heating and is deposited on the surface of the workpiece, so that boron diffuses inside the workpiece, thereby obtaining a good boride film.

If the amount is 50% or more, excess boron oxide is not involved in the boration treatment reaction. As the accelerator, one selected from sodium carbonate and salt is used. Sodium carbonate reacts with the boron carbide powder to produce boron oxide, which causes activated boron oxide, which becomes a heavy phase, is deposited on the surface of the workpiece, and boron diffuses therein, resulting in a good boride layer.

In addition, sodium carbonate is generated by the reaction of boron carbide with CO gas, which acts to cause carburization, which has the advantage of simultaneously performing carburization and boration treatment. Therefore, if it is 30% or more, excessive generation of boron oxide, which generates excessive CO gas or does not participate in the reaction. As an adhesive, the sole chosen from alcohol, a silicone adhesive, and a fluorine adhesive is used. It doesn't matter which one you use. The pressure-sensitive adhesive is adjusted and added arbitrarily according to the composition ratio of the composition, which helps to maintain the shape as a paste when applied to a complex structure of a material to be treated or a large object.

The heat treatment temperature, time and composition ratio have an organic relationship. When the temperature and time are 650 ° C. and less than 1 hour, it is difficult to form a boron layer having a thickness that can withstand wear, and it is 1000 ° C. or more and 10 hours or more. In this case, an unnecessary boron layer is formed as well as an economic disadvantage. The following shows an embodiment of the present invention.

Table 1 shows a mixing example of each composition and its composition ratio, and Table 2 shows the heat treatment and boron penetration depth for [Table 1].

Example 1

After removing the rust on the surface of the general low carbon steel, the oil was degreased and degreased and cleaned. 30 g of boron carbide powder, 60 g of boride boride powder, and 30 g of silicon carbide powder were applied to a selected portion of a paste prepared by mixing well with 30 g of a silicone adhesive, and then dried at room temperature for 10 hours.

After injecting the argon gas and heat-treating at 950 ° C for 3 hours, the compound layers of the specimens were examined. As a result of measuring several places of the Fe ₂ B and FeB layers, various hardness (HV) of distribution outside the range of about 1200-2000 at thickness of 150μm Indicated.

Example 2

30 g of boron carbide powder, 60 g of boric fluoride powder, and 30 g of silicon carbide powder were mixed with an alcohol, applied with a brush, and placed in a Ferro-Boron powder in a degreasing steel surface obtained as in Example 1, at 3 ° C. at 950 ° C. without an atmosphere gas in a heat treatment furnace. The specimens were examined after time treatment. When the Fe ₂ B and FeB layers were measured at 100 μm of the compound layer thickness, various hardness (HV) of 1200-1800 was found. In the above examples, only two were mentioned, but the same test as described in [Table 1] and [Table 2] was performed.

As shown in Table 2 of the present invention, the boron penetrating depth is represented by a shell cloth, indicating that the required boron penetrating depth can be arbitrarily adjusted according to the above conditions.

TABLE 1

TABLE 2

Claims (3)

Boron carbide (B ₄ C) powder 5-60 wt%, Carbofluoride (KBF ₄ ) powder 5-80 wt%, Silicon carbide (SiC) powder 5-40 wt% and boron oxide (B ₂ O ₂ ) powder 50 A boronization treatment agent on the surface of iron or iron alloy, characterized in that the composition is selected or mixed in an amount of up to 30% by weight, and the composition is selected from 30% by weight or less in an accelerator or an adhesive. The boron treatment agent for iron or iron alloy surface according to claim 1, wherein the accelerator is selected from salt and sodium carbonate or mixed, and the pressure sensitive adhesive is one selected from alcohol, silicone adhesive and fluorine adhesive. Boron carbide (B ₄ C) powder 5-60 wt%, Carbofluoride (KBF ₄ ) powder 5-80 wt%, Silicon carbide (SiC) powder 5-40 wt% and boron oxide (B ₂ O ₃ ) powder 50 It is characterized in that the paste is made by selecting or mixing in a weight% or less, and selecting or mixing among an accelerator and an adhesive, and selectively applying the boron treatment agent only to the required part of the object to be treated and heat-treated at 650-1000 ° C. for 1-10 hours. Boron penetrating surface treatment method of the surface of the iron or iron alloy.