JPS6021220B2 - Corrosion prevention treatment method for metal zirconium processed products - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for anticorrosion treatment of zirconium processed products used as corrosion-resistant structural materials.

Pure metal zirconium is a metal with hexagonal crystals and a transformation point of 86?0. Conventionally, it was often processed as is and used as a corrosion-resistant material, but the influence of trace impurities present in pure metal zirconium The disadvantage was that corrosion occurred.

In other words, metal zirconium has a strong affinity with hydrogen, oxygen, and nitrogen gases, and easily forms these compounds, and iron, chromium, magnesium, chlorine, hydrogen, nitrogen, etc. have a negative effect on corrosion resistance.

Generally, in the production of metallic zirconium products, a metallic zirconium sponge is first formed into an ingot by multiple vacuum melting, and after this ingot is forged, it is peeled and rolled. It is manufactured by repeatedly using a moth duller to finish it into a plate of a specified thickness.In this manufacturing process, it is extremely important to reduce the amount of iron and chromium, which are most likely to be mixed in from the container when manufacturing metal zirconium sponge. It's difficult. The above-mentioned impurities are polarized during the melting and casting process, and furthermore, intermetallic compounds are scattered.

The presence of such impurities resulted in an increase in the amount of corrosion of zirconium under severe corrosive environments.

The present invention has been made in view of the above points, and when manufacturing a zirconium processed product by vacuum melting metal zirconium sponge, processing such as forging, rolling, and brazing, it is possible to reduce heat during the process of manufacturing the processed product. A method for anti-corrosion treatment of metallic zirconium products, characterized in that after rolling and before cold working, heating to a temperature of 800°C to 1000°C to form a port, and in the solution treatment, the crystal grains are The solution treatment is carried out in an inert gas atmosphere without cooling the metal zirconium at a rate of 15 to 40 mm per second. The present invention relates to the method.

This resulted in the effect of significantly increasing corrosion resistance.
To explain the process of the present invention, first, a plurality of zirconium sponge blocks are welded using a welding machine, and then melted and cast in a vacuum melting furnace. 800 ingots obtained by this
Hot forging is carried out at around 800°C and further hot rolling is carried out at around 800°C. Next, this rolled material is heated to 800qC~10
Solution treatment is performed by heating to a temperature of 0 to ○, and after this solution treatment, it is subjected to cold pressure (processing), competitive hammering, pickling, and polishing to produce metal zirconium processed products. Conventionally, the solution treatment was not performed, but it was discovered that without this treatment, trace impurities contained in metallic zirconium would not diffuse sufficiently, resulting in a deterioration in corrosion resistance. .

In the present invention, impurities that are polarized in metallic zirconium are sufficiently diffused by heating to a temperature of 800% to 1000°C and solution treatment as described above, and the effects of the presence of impurities are blunted. This significantly increases corrosion resistance.

In the solution treatment, if heating exceeds 1000° C., the crystal grains will become coarse, and if the crystal grains exceed 40 μm, corrosion will increase. Moreover, if it is less than 800:00, the effect of increasing corrosion resistance is lost. After the solution treatment, rapid cooling is performed at 150° C. to 400° C. per second to prevent impurities from precipitating at grain boundaries. Next, an example will be described.

Example 1 ASHMM. Metallic zirconium having a component of R60702 is melted in a vacuum melting furnace and cast into an ingot.

Next, this was forged at 800°C to form a round pillet, and further hot-rolled at 80°C to form a 26-rib cylindrical piece. This 2
6. Heat the birch wood to 900 degrees Celsius and perform solution treatment.
After this solution treatment, water was removed. After this, 2 ships due to cold processing and competing anchors? It was made into a round bar.

Table 1 shows the results of corroding this with various acids.

Also, in Table 1, comparative examples are presented for comparison with conventional products that are not subjected to the solution treatment. As is clear from this table, it can be seen that the amount of corrosion is significantly reduced in the samples subjected to the solution treatment of the present invention compared to those without solution treatment, regardless of the acid.

Table 1 (Unit: mil/year) Example 2 Iron 100Q sail, chromium 110 blood, nitrogen 3, oxygen 10
After forging an ingot made by vacuum melting and casting metal zirconium containing 00 quarts, 1 pine wind, 5 magnesium, and 1 chlorine, it is heated to 900 qo for 4 minutes and cooled with water.

This treated product was corroded for 7 hours in steam in an autoclave at 400° C. and 105 k9/example.

Table 2 shows the increase in corrosion due to this.

At the same time, a comparative example of non-solution treated products exposed to the same corrosive environment is shown. As is clear from this, the solution treatment of the present invention eliminates the segregation of iron and chromium,
It is also seen that the amount of corrosion is significantly reduced. 2 Table The method of the present invention is applicable not only to the materials of the examples but also to the ASTMM
．． R60001. R60702, R60703, R60
It can also be applied to materials such as 704, R60705R60706.

Claims (1)

[Scope of Claims] 1. When manufacturing a zirconium processed product by vacuum melting a metallic zirconium sponge, processing such as forging, rolling, etc., and annealing, after hot rolling and before cold working in the process of manufacturing the processed product, A method for anticorrosion treatment of metal zirconium processed products, characterized by heating at a temperature of 800° C. or higher and lower than 1000° C. for a period of time such that the crystal grain size does not exceed 40 μm, followed by cooling and solution treatment. 2. The method according to claim 1, wherein the solution treatment is performed in an inert gas atmosphere.