Annealing a Connector Part for Crimping2017-10-19

Annealing(*Ref.) is one of the well-known heat treatment process. 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:

1.) Heating the metal to its austenitic temperature.


2.) Maintaining the high temperature so as the material can fully form austenitic grain structure within sufficient time.  


3.) 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 lower down. 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 are running a CNC machining service project for automobile industrial 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 heat treatment, maybe cracked when crimped.

  Cable Terminal without Annealing  


The cable terminal with electrical eyelet is to fit the cable wire, and then crimped for connection purpose. 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 crimping requires the metal with 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 will be conducted by using a pliers is for quality approval. The photo below shows that the cable terminal is more ductile without any cracks.


Cable Terminal after annealing, still ductile after crimping
  Cable Terminal after annealing  


We are well experienced with electrical connector 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 free project review.


*Ref. See more about Annealing in Wikipedia