JPS6058305B2 - Manufacturing method of high toughness, wear and corrosion resistant link chain - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a motor block and a chain block as loading equipment, and relates to a method for manufacturing a link chain having high strength, high toughness, wear resistance, and corrosion resistance.

[Background of the invention]

A motor block or chain block has a mission as a lifting machine.

Direct loads are applied to the link chains used in these systems when lifting and suspending loads, and significant stress may be applied due to abnormal load lifting. For this reason, link chains have high strength, excellent wear resistance because they can withstand wear at the contact parts of link chains, and safety. A link chain that is not only flexible but also tough is required. On the other hand, in recent years, link chains with excellent corrosion resistance as well as strength are desired in the food, medical, and fisheries fields. On the other hand, as corrosion-resistant link chains, link chains made of stainless steel or those coated with various types of plating have conventionally been used. However, stainless steel has the disadvantage that it not only does not provide the required functionality but is also expensive, and when a load is applied to a link chain made of stainless steel, bending stress is generated in the chain. There was a drawback that a difference in elastic strain occurred between the plated layer and the base layer, and the plated portion peeled off, resulting in a significant decrease in corrosion resistance.

[Purpose of the invention]

It is an object of the present invention to provide a method for manufacturing a strong, wear-resistant and corrosion-resistant link chain that eliminates the above-mentioned drawbacks.

[Summary of the invention]

The present inventors have conducted various studies to develop a link chain that is strong, wear-resistant, and corrosion-resistant, and as a result, they have discovered that the above objective can be achieved using a melt having the composition and manufacturing process as shown below.

In other words, a link chain made of steel is carburized or carbonitrided, and Sn2O ~ 60% is added in that atmosphere.
, 5 to 40% of Bl, and 40% of PblO by direct insertion and cooling into a melt, it has been found that a strong, wear-resistant, and corrosion-resistant link chain can be obtained. The temperature of the melt is preferably 250°C or less. By making the melt liquid at a temperature of 250° C. or lower, the quenching cooling effect and the desired strength and wear resistance as a link chain can be easily obtained.

The lowest freezing point of Sn-Bi-P dark gold with the above component composition is 18
It is 0°C. The reason why the Sn-Bl-Pb alloy has the above composition range is that the melting point can be lowered by about 180°C due to the synergistic effect of the three elements Sn, Bl, and Pb.
By inserting the melt into the melt and cooling it from the carbonitriding and normal quenching temperatures, a sufficient quenching effect on the link chain can be obtained. If the composition is other than this, the melting point will be high and the hardening effect will not be sufficient. Second, by inserting the link chain into the melt, the melt adheres to the workpiece, which has a significant effect on corrosion resistance. [Embodiment of the invention] Chemical composition in weight%: C: 0.21%, Si: 0.21
%, Mn; 1.39%, P; 0.013%, S; 0.0
Wire diameter 7.1 mm made of alloy consisting of 11% and residual Fe
We conducted various experiments on the link chain.

In Figures 1 to 3, 1 is the method of the present invention, that is, 870°C
After carburizing for 20 minutes, Sn: 55%, Bi: 10% by direct weight
,,Three powders were inserted into a 210°C melt having a composition of 35% p-Pb, and then quenched and cooled. No. 2 was carburized at 870°C twice, oil-cooled, and tempered at 200°C.

No. 3 was soaked in a Sn bath after the treatment of No. 2.

4 is made of SUS3O4.

FIG. 1 shows the results of the tensile test of the four types of link chains mentioned above.

As is clear from this, it can be seen that Sample No. 1 made according to the present invention and Sample No. 2 of the conventional example are the strongest and have excellent tensile strength and elongation. Figure 2 shows the results of the oscillation fatigue test of the link chain. In terms of fatigue strength, it can be seen that product 1 of the present invention exhibits higher strength than other plated products 3 and 4 made of SUS3O4. Figure 3 shows the rated load of 1t.
The link chain wear test was carried out using an actual 0n motor block in a dry atmosphere.

The results of the abrasion test show that Nos. 1 and 2 have almost the same values within the variation range, but are significantly superior to Nos. 3 and 4, which have corrosion resistance. Next, as a corrosion resistance evaluation, a salt spray test was conducted, and as a result, no red rust was observed for product 1 of the present invention and stainless steel product 4 even after two tests.
No. 2 developed red rust within one hour, and No. 3 developed red rust between 5 and 2 m.

The table shows a comprehensive evaluation of various performance test results.

As a result, it can be seen that the product of the present invention has the best performance in each item, and has excellent toughness and corrosion resistance. Figure 4 shows the manufacturing process for the products of the present invention and a conventional example in which plating treatment is applied to impart corrosion resistance.The manufacturing process can be reduced to about half of the conventional method. Recognize.

〔Effect of the invention〕

Conventionally, plating was used as a simple method to impart corrosion resistance to mechanical structural members, but when strength is required,
In order to perform plating treatment after heat treatment, post-treatment and pre-treatment steps were required.

According to the present invention, since heat treatment and plating treatment can be integrated, it has become possible to significantly shorten the processing steps. The link chain characteristics are also superior to conventional ones.

[Brief explanation of the drawing]

Figure 1 is a characteristic diagram showing the results of a tensile test of a plated link chain, Figure 2 is a characteristic diagram showing the results of a oscillation fatigue test of a link chain, and Figure 3 is a characteristic diagram showing the results of a wear test of an actual link chain. , FIG. 4 is a manufacturing process diagram.

Claims (1)

[Claims] 1 After carburizing or carbonitriding a link chain made of steel material, Sn20 to 60% by weight remains in the atmosphere.
, a method for producing a high-toughness, wear- and corrosion-resistant link chain, characterized by directly inserting the link chain into a molten bath having a composition of 10 to 40% Pb and 5 to 40% Bi, and quenching and cooling the link chain.