The wire annealing process is actually a type of heat treatment that changes the mechanical properties of the wire. These changes basically reduce hardness, increase flexibility and better formability (change in metallurgical structure) and cause the elimination of stresses created in the wires used in the bolt and nut industry. In the annealing process, the wire is heated to a temperature higher than the crystallization temperature in a suitable period of time. The atoms in the crystal network of the wire are moved and the defects and molecular damage caused by the deformation of the wire in the previous steps are corrected and then the wire is slowly cooled.
Cold Heading Quality (CHQ)
It is a process in which steel is produced by annealing and stretching from one size to a smaller size. In fact, (CHQ) includes two important processes. Acid washing + phosphate + wire stretching (SAPPD)
In the table below, there are brief explanations about the types of wires, as well as their usage and CHQ processes.
| Use | Steel Grade | Process | |
| AISI/SAE | JIS | ||
| Pin, Screw | 1008-1010 | SWRM8-10K | HD |
| Bolt, Nut | 1006-10484115-4140 | SWRCH6A-10ASWRCH10A-45K(F) | HD, RAIP, (S)AIP, PASAIP, PSASAIP |
| Bolt, Piston Pin, Safty Bolt | 5130-5147 | SCM415~440(H) | (S)AIP, SAIP, PASAIP, PSASAIP |
| High Tension Bolt, Crank Shaft | 52100 | SCr415-445(H) | (S)AIP, SAIP, PASAIP, PSASAIP |
| Bearing | 51B20 | SUJ2 | PASAIP |
| Bolt, Construction High Tension Bolt | 10B21-10B38 | SCr420B-440B | HD, (S)AIP |
| HD | W/R – PC – SKP – PK | ||
| (S)AIP | W/R – P – SA – PC – SKP – PK | ||
| RAIP | W/R – P – WD – RA – PC – SKP – PK | ||
| SAIP | W/R – P – WD – SA – PC – SKP – PK | ||
| PASAIP | W/R – P – LA – P – WD – SA – PC – SKP – PK | ||
| PSASAIP | W/R – P – SA – P – WD – SA – PC – SKP – PK | ||
| SAPC | W/R – P – SA – PC – PK |
W/R (Wire Rod)– P (Pickling)– PC (Pickling&Coating)– WD (Wire Drawing)– SKP (Skin Pass)
LA (Low Temperature Annealing)– RA (Regular Annealing)– SA (Spheroidized Annealing)– PK (Packing)