Hot rolled steel failure analysis.
Hot rolled steel failure analysis.
(OP)
I am a independent laser mechanic. I have a client that cuts commercial saw blades. In the past they have machined the teeth out of the stock material. Recently they have been cutting the saws on the laser. The problem is, sometimes, they have a 90% failure rate. The teeth of the saw blade break off right at the shoulder of the tooth.
Is there someone who can recommend a consulting company to look at this problem. It is my feeling that the blade is becoming tempered by the laser and causing a brittle zone where the cracks form and propagate.
Or any thoughts in general would be great.
Is there someone who can recommend a consulting company to look at this problem. It is my feeling that the blade is becoming tempered by the laser and causing a brittle zone where the cracks form and propagate.
Or any thoughts in general would be great.





RE: Hot rolled steel failure analysis.
RE: Hot rolled steel failure analysis.
http://www.nwlabs1896.com/
RE: Hot rolled steel failure analysis.
RE: Hot rolled steel failure analysis.
To give a bit more information, they are 10" saw blades, but they are for cutting plywood in a commercial setting. The RPM are something like 10 times that of normal table saw.
Let be bounce this Idea around. The laser, as you may imagine, cuts at a pretty high temperature. The shield gas they are using is nitrogen at about 150 psi and 15-20 cfm. The nitrogen comes from a liquid cylinder, turned into vapor/gas and the output through the same orifice as the beam. My question is, could the gas quench the molten steel fast enough to change the material properties in the heat effected zone? Or, is the effect of the cold gas going through an "expansion orifice" negligible?
Also, in response to the tempering comment in my first post, my terminology is a little rusty, its been a while.
Robert you mention the idea of a tempering operation. To me, that means cooking the saws at about 1100 degrees for about an hour. That is an option. Before I recommend it let me ask this, Because the steel comes from a coil, flattened, and then shipped to my client, in your opinion, or anyone's, would a tempering operation warp the saws? Would the saws want to return to the shape they were in when they were on the coil?
RE: Hot rolled steel failure analysis.
RE: Hot rolled steel failure analysis.
RE: Hot rolled steel failure analysis.
Just out of curosity as you state your starting material is hot rolled and my question is how do you process the material prior to machining?
As for annealing, we used to make some disk out of AISI 1060-1065 with a large number of holes that was about 0.125" thick and we annealed the disk at 1000F with no problems. The disk we in a rach and the disks were on edge. The only thing we did extra was we brought the oven up slowly.
RE: Hot rolled steel failure analysis.
RE: Hot rolled steel failure analysis.
Learn the rules,so you know how to break them properly.
Dalai Lama
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RE: Hot rolled steel failure analysis.
Yup, they are 10" blades with about 100 to 120 teeth on them. What is interesting, is these are the only saws with broken teeth. These saws do have inserts on them but that part is common to both laser cut and machined saws. The "Cast" you see is from Oxygen cut, instead of nitrogen.
As far as processing before machining, I would have to check with my client to see what they are doing.
As far a laser cutting steel with Manganese, my wife says there may be some concern about the fumes, but I'll try anything once.
RE: Hot rolled steel failure analysis.
Dik
RE: Hot rolled steel failure analysis.
Maui
RE: Hot rolled steel failure analysis.
RE: Hot rolled steel failure analysis.
RE: Hot rolled steel failure analysis.
I'll have to check with the client to see what type of pictures they have. I'll post asap.