Tag: Thread rolling

Thinking Precision, Thinking Big- Keystone Threaded Products

Posted on by

The Team at Keystone Threaded Products shows us that “Precision” doesn’t necessarily mean “Tiny” as they thread the ends of some 20 foot long, 10 inch stainless steel bars for a Metalworking press. The thread is a 10-1/4″ : 4 UNJ RH applied to  each end of the  3 and a half ton bar.

@0 feet long two ends to thread, 3 and a half tons of precision.
20 feet long, two ends to thread, 3 and a half tons of precision.

At Keystone, they roll the thread form onto the material which makes for a stronger thread. Alignment and following the process is critical to assure a good thread.
Thread rolling dies create the thread form on the workpiece.
Thread rolls create the thread form on the work piece.

Multiple passes are needed to build the thread up to the proper dimensions.
HAldf a million pounds of pressure are imparted on the rolls to plastically move the steel of the bar into the thread form. Read the gage.
Half a million pounds of pressure are imparted on the rolls to plastically move the steel of the bar into the thread form. Read the gage.

Obviously it takes knowledge, skills, and experience to apply half  million pounds to produce precision work.
Rich says that he's rolled larger bars, but the confidence that skills and experience and a great team to work with make precision manufacturing a great career.
Rich says that he’s rolled larger bars, but  skills and experience and a great team to work with  create the can do spirit that makes precision manufacturing a great career.

Here’s another look at a finished bar. Precision does not necessarily mean tiny!
Just another point of view so you can see the size of the work.
Just another point of view so you can see the size of the work.

 
Thanks to Betsy Minnick and the Team at PMPA member Keystone Threaded Products for showing us that “Precision” is not a synonym for “Tiny.”

Cold Work And Steel Parts

Posted on by

Cold work is defined as the plastic deformation of a metal below its recrystallization temperature.

In the precision machining industry, cold working processes can include thread rolling, thread forming, swaging, crimping, staking, planishing, and metal spinning.

And the steel bars that we machine are typically cold drawn (cold worked.)

Our suppliers use cold work when cold drawing a bar from hot roll to make it more machinable.

How to recognize a cold work process: No heat is added and no chip is removed in the process of moving the metal into shape.

Cold working of steel

  • changes its mechanical properties
  • and improves its surface finish.

Tensile strength and yield strength are increased by the cold work while ductility (as measured by % elongation and % reduction in area decrease.

See our post here.

Steels with low carbon contents, low residuals, low Nitrogen levels, and made by the Basic Oxygen Process readily cold work- think 1008, 1010, etc..

Cracks can develop after cold work is performed on machined parts.
Cracks can develop after cold work is performed on machined parts.

Intentionally adding nitrogen  can make predispose a part to cracking during cold work. If a part needs to be crimped, swaged, staked or otherwise cold worked after machining, You should make certain that the steel is not renitrogenized. (Nitrogen intentionally added during the melt process).

Also, make sure that the cold work in cold drawing was standard draft rather than heavy draft. Heavy draft reduces the ductility remaining in the bar- but makes the chips easier to separate.

We posted about these issues here.

More information on Nitrogen in free machining steels.