Annealing(*Ref.) is one of the well-known heat treatment processes. Commonly used in applications where a component is bent or crimped, it lowers the possibility of metal cracking during the cold-working process. In APPORO, we provide annealing heat treatment service for customized CNC parts.
A complete annealing process for steel involves:
- ) Heating the metal to its austenitic temperature.
- ) Maintaining the high temperature so that the material can fully form an austenitic grain structure within sufficient time.
- ) Slowly cooling down in the furnace to obtain equilibrium micro crystal structure.
After that, the hardness, yield strength and tensile strength of ductile steel will decrease. That is why the annealed metal is much softer and suitable for further cold working, such as bending, stamping, extrusion, rolling or forging.
Case Study about Cable Terminal Annealing
Recently, we ran a CNC machining service project for an automotive application. The item is a cable terminal with electrical eyelet, made of free cutting steel 12L14 with blue zinc plating surface treatment. The cable terminals were well machined, zinc plated and inspected by APPORO. However, our customer rejected the first articles as they cracked when crimped. See the photo below.
Cable Terminal without Annealing
The cable terminal with electrical eyelet is designed to fit the cable wire and is then crimped for connection purposes. However, although the metal is good for cold working, it usually lacks ductility and is brittle, therefore not preferable for further crimping process. Generally speaking, a perfect crimp requires the metal to be in a softer and more malleable state. In that way, annealing can be the best treatment to solve this situation.
As a result, we sent the cable terminal for annealing prior to zinc plating process. After annealing, a crimping test is conducted using pliers for quality approval. The photo below shows that the cable terminal is more ductile without any cracks.
Cable Terminal after annealing
We are well experienced with electrical connectors due to our CNC machining services production lines. You can visit our official site to have more ideas about our core services. Should you have any inquiry for above items, do not hesitate to send us RFQ for a free project review.