SCS steel is seen as the new alternative to P&O flat-rolled steel. Why? SCS inhibits rust with no surface coating, no special packaging or storage requirements. Pickling removes scale by running the sheet through an acid bath. SCS removes all but a microns-thin layer of scale, using a patented brushing process and water. With P&O, after the acid bath there are also rinsing, drying and oiling steps.

So P&O and SCS each have unique, different process costs.
The crucial question is “What’s the difference in cost?”

  Economics 101: SCS vs. P&O

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  An Idea for Fabricators . . .
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To find out, you need to examine the components of variable cost for each process: labor to run the process, materials and supplies consumed, energy required and waste disposal cost. Such factors
will vary among P&O lines based on technology, capacity and even location. However, on average, variable processing costs of pickling operations equate to a fairly consistent $15 per ton.

SCS variable process costs?
    - Labor:         $1.00/ton
    - Brushes:    $  .84/ton
    - Filters:        $  .20/ton
    - Electricity:  $1.40/ton
      TOTAL:       $3.44/ton

The $11.56/ton variable cost difference is crucial to steel finishers who must compete on price. They find they can sell SCS at the P&O price (and often at a premium) yet enjoy a lower cost . . . which translates
to better margins. And the cost difference grows as these different processes move further along the steel supply chain. To see a complete SCS vs. P&O economic comparison >read more<

Here's a way to double productivity when laser cutting flat sheet -- cut two sheets at a time (if your laser is powerful enough for the extra thickness). Same laser, same speed, same consumables - but two parts drop out of each cut!

Easier said than done - especially for thick parts and very small parts. The culprit that most often limits lasering double stacks is gaps between the sheets being cut. A small gap or irregularity that keeps the sheets from being perfectly flat and parallel may cause the top part to hang up, so it doesn’t drop through the bottom sheet. Removing the part by hand negates productivity gains from double stack cutting. But, if your sheets are consistently flat and parallel - no gaps - then double stack lasering becomes possible.

With P&O sheets the possibility isn’t there. The oil on the sheets creates a small gap itself. The oil's stickiness traps dirt and particles between the sheets, creating larger gaps. Finally, oil can make sheets stick together in such a way that small air pockets are trapped between the sheets (See Figure 1).

Even if the oiled surface didn’t create gaps, the lasering process itself often does. The sheets may look perfectly flat, but retain residual stress that is not removed, even by roller leveling. This stress causes the sheet or the part (or both) to experience 'springback' when lasered. The resulting deflection acts much the same as a gap, causing the top part to hang up instead of dropping.

It’s no wonder fabricators gave up on lasering double sheets a while ago. But it’s time to re-examine this idea, because trials performed on SCS show that double stack laser cutting of SCS is a viable fabrication practice. SCS overcomes the limitations of P&O:

                - with no oil, you get “metal touching metal” (see Figure 2);
                - with no oil, there are no dirt or air gaps created;

In addition, stretcher-leveled SCS sheets have no residual stress and don't spring back during lasering.

Trials of laser cutting double stacked SCS sheets produced identical parts of excellent quality and there was no need to slow the laser speed. Best results were achieved when parts were first cut near the sheet's periphery and then toward the center. If you begin cutting in the center of the sheet, the laser heat can't dissipate quickly enough, causing a small gap to open between the sheets that hangs up the top part.

If your operations involve significant laser cutting, we urge you to try double stack lasering of SCS for your high volume parts. Contact us for additional information and visit www.scsprocess.com to view parts that were made by double stack laser cutting SCS.