×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Problem with cutting steel bars

Problem with cutting steel bars

Problem with cutting steel bars

(OP)
Hello all.

I have a problem where I work and want your help.
At forging, when the steel bar is cut, sometimes the bar sticks to the "cutting blade". Then, it takes different shape than the normal one and a defect appears. The process is mechanical, no cutting disc is used.
It's like the bar acts like a dough.
What can we do so this problem doesn't occur?

Thanks in advance!

RE: Problem with cutting steel bars

If the bar is sticking, then it's possibly too hot, and some form of cooling is needed. Usually, there's a cutting oil that is used to cool the cutting tool and cut.

TTFN
FAQ731-376: Eng-Tips.com Forum Policies

Need help writing a question or understanding a reply? forum1529: Translation Assistance for Engineers

Of course I can. I can do anything. I can do absolutely anything. I'm an expert!

RE: Problem with cutting steel bars

Temperature and lubrication are the two issues.
The sticking ones are either too hot, or not enough lube, or both.

= = = = = = = = = = = = = = = = = = = =
Plymouth Tube

RE: Problem with cutting steel bars

Like a dough? Is the cast metal still soft enough when cut to actually deform or move under its own weight?

RE: Problem with cutting steel bars

(OP)
racookpe1978, it's not cast metal, it's a solid metal, that's heated by induction and then cut.
I thought about lubrification but need to investigate the problem more.
Thanks guys.

RE: Problem with cutting steel bars

Is this an automated process? Does the machine manufacturer have anything to say in the O&M manual or on the phone?

the way you said it is " heated by induction and then cut" I'm assuming you heat just the section you want to cut, perhaps because it is a thick section.

Does the "defect" resemble the edge on this cold sheared plate?
http://images.discountsteel.com/files/image/oms_pr...

RE: Problem with cutting steel bars

(OP)
I can't see very clearly, but I think so.

RE: Problem with cutting steel bars

My opinion - and without looking at a video in real time of the sawing operaton and metal temperature of the steel being cut I'm making sort of a guess here - is that the "soft, doughy" steel is getting torn by the saw teeth - not "cut" cleanly by the saw teeth. Then, as the blade pulls the torn metal past the cutting area, it tears and pulls more soft metal from the sides and back of the cut down into the cut and in between the teeth. Eventually, the excess friction between blades and material siezes the blade.

The "goo" squeezes the blade as it seeps back into the cut (think Panama canal's Gailliard Cut: As you remove material more flows back into the groove and gums up the teeth).

RE: Problem with cutting steel bars

Just to be clear, the steel bar being saw cut is a piece of heated raw material that immediately gets hot forged after cutting? Or is the saw cut performed on the part immediately after hot forging?

Saw cutting a hot steel part may likely result in some welding between the blade and part surfaces. It would be better to saw cut the material while cold so a cutting fluid can be used. If you really need to trim the material while hot, you might consider using some type of shearing or trimming die.

RE: Problem with cutting steel bars

(OP)
tbuelna, it's not a cut made by sawing, it's a mechanical process made by a guillotine.
racookpe1978, I think you're very accurate with what you said.

I informed myself a little better about the problem.
When the guillotine makes the first "cut" , it goes blank 3 more times(it's idling) without cutting, and it goes by the bar that's advancing little by little. This is where sometimes the problem occurs.

I hope my English is not that bad and you guys understand the process that I'm explaining.



RE: Problem with cutting steel bars

How are you cooling the blade while it is in the 3x idle time?

What are blade approach temperatures, blade removal surface temperatures? That blade is very thin - it will heat up quickly!

RE: Problem with cutting steel bars

Blade wear could be part of your problem. Uneven heating through the cross section of the bar could also contribute as well as the above responses.

RE: Problem with cutting steel bars

(OP)
It's not cooled.

RE: Problem with cutting steel bars

EN,

Your English is fine, but your communication would be enhanced with a sketch.
- Can you sketch the cut end with and without the defect?
- can you sketch what the guillotine and the support provided for the bar during the cut look like?
- does the bar continue to advance during the cut operation?

RE: Problem with cutting steel bars

EN-

Thanks for the partial clarification. So what I understand so far is that you are locally induction heating a piece of wrought steel bar and then cutting the bar at the heated area using a single blade shearing operation. But for some reason you are not getting a clean separation at the shear plane. I assume you are using a machine designed specifically for hot shearing steel, but have you checked to see if you are using the proper blade and machine settings for the material type, size and shape you have? Also, as others noted, are you sure the material has the correct temperature all through its thickness when it is being sheared?

More specific details about the machine and settings used, material composition and form, process variables such as temperatures, cycle times, etc., and some photos of the defective cuts would be extremely helpful.

Regards,
Terry

RE: Problem with cutting steel bars

(OP)
What you said, is correct Terry.

But the process is like 20-30 years old and the temperature I think it's good, maybe needs a little optimization.
Only sometimes this problem occur. Now engineers are investigating the problem.
When I'll have more details, will let you know. I hope tomorrow.

btrueblood, I will make a sketch when I'll get into more details of the problem.

Thank you again.
Be back soon with more details.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources