Blackening treatment and connection method for steel structure bolts

Blackening treatment and connection method for steel structure bolts

Steel structural bolts belong to the category of fasteners in hardware, and most of the colors we see are black. Ordinary bolts are generally made of ordinary carbon structural steel without heat treatment, while high-strength bolts are generally made of high-quality carbon structural steel or alloy structural steel, requiring quenching and tempering heat treatment to improve comprehensive mechanical properties.

The treatment methods for blackening of steel structural bolts mainly include the following:

1. BRN processing method.

In specialized equipment, use specialized ion modification methods for treatment. Has good film adhesion; Beautiful surface color; Good wear resistance; The surface is dense; Controllable film thickness; Advantages such as non discoloration and non detachment.

2. Chemical heat treatment method.

Steel structural bolts are treated in specialized equipment, with a firm film layer and good adhesion; Beautiful color and luster; Good wear resistance; The surface is dense.

3. Electrolytic oxidation method.

The film layer is thick and black, with poor sun resistance and easy to burst automatically.

4. Chemical blackening method.

This method is divided into two types: acidic black and alkaline black. The acidic black color of the film layer results in uniform color, thin and firm, elastic, and good adhesion, but the film layer is porous and has poor wear resistance, requiring curing treatment to improve wear resistance. Alkaline blackening takes a relatively long time, but the black film has good wear resistance and does not require curing treatment.

The above is the treatment method for blackening of steel structure bolts, which we can often use. In addition, there are two connection methods for steel structure bolts, one is the cold processing connection method for high-strength bolts, and the other is the Hot working connection method for high-strength bolts.

During production and processing, we can choose according to different requirements when using. Cold processing connection is rigid connection, while Hot working connection is flexible connection.