Slivers On Rolled Steel Products

May 17, 2012

Slivers are elongated pieces of metal attached to the base metal at one end only. They normally have been hot worked into the surface and are common to low strength grades which are easily torn, especially grades with high sulfur, lead and copper.”- AISI Technical Committee on Rod and Bar Mills, Detection, Classification, and Elimination of Rod and Bar Surface Defects

Slivers are loose or torn segments of steel that have been rolled into the surface of the bar.

Slivers may be caused by bar shearing against a guide or collar, incorrect entry into a closed pass, or a tear due to other mechanical causes. Slivers may also be the result of a billet defect that carries through the hot rolling process.

This is my lab notebook sketch for slivers ‘back in the day…’

Slivers often originate from short rolled out point defects or defects which were not removed by conditioning.

Billet conditioning that results in fins or deep ridges have also been found to cause slivers and should be avoided. Feathering of of deep conditioning edges can help to alleviate their occurrence.

Slivers often appeared on mills operating at higher rolling speeds.

When the frequency and severity of sliver occurrence varies between heats,  grades, or orders, that is a clue that the slivers probably did not originate in the mill.

This is how Slivers present under the microscope. Note decarburization (white appearance.)

Slivers are often mistaken for shearing, scabs, and laps.  We will post about these other defects in the future.


Metals Thefts – Ohio Leads Nation

March 22, 2012

The high price of copper and other base metals has led to an increase of metal theft incidents across the country, and Ohio leads the nation for insurance claims resulting from the crime. 

Copper thefts continue to rise. Copper from air conditioning stolen from this church.

Insurance claims linked to metal theft across the country jumped to 25,083 between 2009 and 2011, up 81 percent from the three-year period between 2006 and 2008, according to a new report by the National Insurance Crime Bureau.

The report showed insurance claims for metals thefts were up 81% from the last report covering 2006-2008.

The top five states generating the most metal theft claims

  •  Ohio (2,398);
  • Texas (2,023);
  •  Georgia (1,481);
  •  California (1,348);
  •  Illinois (1,284).

The top-five Core Based Statistical Areas generating the most metal theft claims:

  •  Chicago-Naperville-Joliet, IL (963);
  • New York-Northern New Jersey-Long Island, NY-NJ (921);
  • Atlanta-Sandy Springs-Marietta, GA (823);
  • Dallas-Ft. Worth-Arlington, TX (674); 
  • Detroit-Warren-Livonia, MI (587).

Copper theft is the most common item for the crime, and thieves have stolen copper piping and wiring from churches, abandoned homes and buildings, construction sites, cellphone towers and other unguarded properties, as well as from manufacturing plants.

Anyone with information concerning metal theft can report it anonymously by calling toll-free 1-800-TEL-NICB (1-800-835-6422), texting keyword “fraud” to TIP411 (847411) or by visiting our Web site at www.nicb.org. Or, iPhone or iPad users can download the NICB Fraud Tips app to make it easy to quickly send a tip and get a response

One Northern California Company provides a high tech  service to help protect property.

Video.

Photo


Steel, Master of Them All

November 15, 2011

Gold is for the mistress

Silver for the maid

Copper for the craftsman, cunning at his trade,

“Good!” said the Baron, sitting in his hall,

“But Iron- Cold Iron – is Master of them all.”

-Rudyard Kipling

Full poem here

In 1910 when Rudyard Kipling wrote this verse,  the USA produced about 24 million tons of steel. That amounted to roughly 482 pounds for each of the 92.2 million americans counted in the census that year.

In 2010, the US produced 88.5 million tons- down 13% from 2008 and down 18% from 2006 and 2007. That 88.5 million tons- amounted to about 575 pounds for each of the 308 million Americans alive that year.

That’s an increase of about 20%  per person over a period of a hundred years?

Only 20%?

What amazes me is that all of our devices using steel have diminished the mass of the steel needed to do the same job.

This 1910 Case tractor probably weighed in around 3000 pounds and delivered no more than 20 horsepower.

This 2010  production single cylinder Kohler (iron cylinder) engine equipped Cub Cadet also rated at 20 horsepower:

I don't think this one weighs 3000 pounds...

Steel truly  is the master- in this case the master of doing more with less.

Buckminster Fuller describes this decreasing of mass but increasing of capability as “ephemeralization.”

Its something my kids have seen growing up as they observed our communications technology:

This is what a cell phone was when my kids were born in the 1980's.

Cell phone today:

Oh the one in the 1980's didn't bring me my newspaper or have a virual assitant or play movies either. It was ...just...a ...phone!

Steel may be the Master of Them All, but  it is Engineers, and Machinists and other manufacturing craftsmen who are the real masters – we make the stuff that makes our modern world- Modern.

Case tractor photocredit: Thanks Big Red!

Cub Cadet photocredit:

Motorola Brick

Apple iphone 4s


Prices Rise As Manufacturing Recovers

September 2, 2010
The prices of all raw materials that we track rose as follows over the past year:
Aluminum: Up 23% from July 2009.
Brass: Up 28% from July 2009.

Copper: Up 17% from July 2009.

Nickel: Up 70% from July 2009.

Stainless: Up 37% from July 2009.

Steel, Busheling: Up 51% from July 2009.

China Coke, Up 3% from July 2009.

Up some serious double digits over a year ago.

You can download the August Material Impacts report free here

We track these items as they indicate the direction that we wll be paying for our raw materials in our precision machining shops, Steel, Aluminum, Brass and Stainless barstock. These items are critical to the manufacture of those materials. 

 

 

 

Share


Materials Prices Increase-Through The Roof

April 8, 2010
6 of 7 materials we track up 44-114%

6 of 7 materials we track up 44-114%

Prices of raw materials used to make precision machined products are up substantially,  ranging from 44% to 114%  from March 2009- March 2010 for 6 of the 7 materials we track.

 Low inventories, increasing demand, idled production facilities, are among the factors involved here in North America.

As are the historic iron ore agreement  and continued high demand in China. 

We think this trend will be around for a while...

Fuel price increases also impact freight, which is an important factor in our business.

We will not be shocked to see monies paid for steel in May to be $80 per ton higher than they were in April based on already announced price increases and the current price on  #1 busheling which determines surcharges.

Read more and download the .pdf report  here.

Photocredit.

Share


Carbon Equivalent And Weldability

December 29, 2009

The weldability of steels is influenced primarily by the carbon content. At higher carbon levels, steels may need either pre- or post- weld heat treatment in order to prevent stress build up and weld cracking.

Generally speaking, if the Carbon Equivalent (CE) is 0.35 or below, no pre- or post- weld  thermal treatment  is needed. In our experience with maintenance welding, we have found that preheating was beneficial between 0.35 and 0.55 CE. Above 0.55 CE we usually both pre- and post- weld heated to relieve stress and prevent cracking.

So CE= .35 max.

However the other elements that are contained in the steel also have an effect on the steel’s “carbon equivalence.” These additional elements can really add up in scrap fed electric arc  furnace steels that now predominate in our market.

Electric Arc Furnaces are predominately scrap fed.

Photo credit.

Here are two formulas for calculating Carbon Equivalents.

CE=%C+(%Mn/6)+(%Cr+%Mo+%Va)/5 + (%Si+%Ni+%Cu)/15

This is the first formula I learned when I took over metallurgical support for  maintenance ‘back in the day.’

In this formula you can see that 6 points of Manganese are approximately equal to one point of Carbon.  5 points of Chrome, Moly or Vanadium are roughly equal to a point of Carbon, while it takes about 15 points of Silicon, Nickel or Copper to get about the same effect as one point of Carbon.

The GE formula for Carbon Equivalency is CE= C+(Mn/6)+(Ni/20)+(Cr/10)+(Cu/40)+(Mo/50)+(Va/10). If this is less than .35 max, you should have no need to pre or post weld thermal treat in most cases.

As long as CE is no more than .35, you probably won’t need to preheat or post weld stress relieve your welded parts. above .35 CE, you may need either or both depending on section thickness and CE.

* (I) added (extra parentheses) to keep (the terms) clear in (this post); no (scathing rebukes) from (math teachers) please!

Share