Wire Cracking Issue

Hello,

New to this forum and drawing really.

I have an issue that I can't seem to find a solution to...vertical cracking on the drawn wire.

Here is what I am running:

Starting size: 8.5mm
Final size: 0.225"
Draw steps: 0.335" > 0.290" (25%) > 0.254" (23%) > 0.225" (22%)
Draft angles: 16 deg / 14deg / 12deg
Lubricant: Calcium Based
Draw speed: ~150fmp
Material grade: C1035
Descaling: Mechanical Reverse Bend

I have noticed that whenever there is a crack, the area of the wire is shiny; however, when it is shiny, it doesn't always have a crack. I have also noticed that the crack can occur anywhere between the 3 draws, even after the first draw.

I have done the following experiments:
- Trialed 5 different soaps
- Trialed lower carbon grade material (C1012)
- Decreasing draw speed to 50%
- Changing to single piece die instead of inserts

None of which showed promise.

Now I am onto the descaling process. Is it possible that I am leaving too much scale on the wire before the ripper die, causing scale/shavings to travel into the soap box? Can these shavings, consequently, cause a blockage in the entrance of the die?

Any help is appreciated.
Thank you!!!

The drawing practise as mentioned seems correct . No reason to damage the steel.

No mention has been made of rod quality which it is where it seems to be the problem.
The rod can have the following problems :a) surface defects, b)pipe, c)Inclusions ,
c) Inadecuate metalurgical structure due io inadecute of control cooling during the process (must likely to be the problem)

Eduardo Anaya

Thank you Eduardo for the quick reply.I have previously reached out to the mill regarding the issue and they have performed tests on the suspect wire; however, deem it as not material related. I have attached a picture of the scale spalling I see on some of the incoming raw material. Is this just a surface defect inherent to hot rolled material? Will it be detrimental to the drawing process?

Ask the rod mill for micro structural analisys of the rods it should show the presence or not of mayor defects.
Also ask for rod section analysis .
Send them wire breaks for them to identifie the cause of the breaks
Regards
Eduardo





also

The sent surface pictures of rods do not show mayor problem

Please send picture of the breaks