use. Resource reduction was more com- plicated (and proprietary). According to Boyd, the new plant was outfitted with process controls that would allow it to increase its yield. What’s more, the capabilities of the machines purchased (which are among the fastest horizon- tal centrifugal casting machines in the industry) allowed the new plant to produce pipe with thinner walls than could previously be made. “[Pipe has a] metal thickness standard—a minimum and maxi- mum—but we now have improved control of metal thickness to operate comfortably within standards,” Boyd said. “And the closer you can come to the minimum, you are saving metal.” The labor reduction was the most important improvement made at the new plant, according to Boyd, and it was a twofold effort. The first stage of the reduction involved working with the employees’ union to allow cross-
Pipe enters the heat treat ovens. Special burners at the front of the furnace and consistent spacing allow the oven to achieve greater capacity.
Pipe exits the oven and descends to an extended conveyor in an elevator. The long conveyor allows the pipe to cool, as opposed to using air or water.
6 7
training. According to traditional union practices, workers are expected to do their contracted job and nothing else. But in order for the Marvel City Mini Mill to exhibit the flexibility of work- force necessary to match that of the steel industry, the workers had to be willing to adapt to multiple job defini- tions. According to Pensec, the people employed at the Mini Mill are all clas- sified according to one job definition and are trained (at their own expense) to go from job to job throughout the manufacturing process before they are qualified to be hired. And the training process is no easy road—to date, only 47% of the people who have gone through the training have been hired. “The people here are far different
from anything I’m used to,” said Plant Manager Paul Pereira. “We have only one job classification. In most union shops, there are lots of classifications by area.”
9
The second effort was to automate
several areas of the plant that were pre- viously manual, including the transfer of metal from the holding furnaces to the pouring ladles and movement of solidifying pipe from the pouring lines to the heat treating furnace. The plant also was built above
ground, essentially on stilts. This was done to avoid equipment ruination in the event of flooding, but it had the added benefit of making the plant easier to maintain, as the inner workings of the equipment can be accessed without descending into pits, which are often built into the floor of other facilities. The Marvel City Mini Mill also operates a high efficiency annealing furnace, which uses heat recovery and special burners to reduce energy consumption and emissions. Finally, because the new plant has
more space to work with, U.S. Pipe now can produce products to the in-
The pipe is filled with concrete in a process similar to casting.
10 11 12
The pipe is coated with water-based paint.
A stripe showing how the pipe should be assembled is painted on each piece.
Inspection for final packaging is performed automatically.
8
Ductility and pressure testing and a physi- cal inspection are performed as the pipe moves down the conveyor.
MODERN CASTING / July 2010
13
The pipe bundles are staged and shipped.
19
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60