GENERAL
All sizes of Grip-Lug® grouser bar can be installed on grouser shoes using machinery made for such purpose. Grouser reconstruction using semi-automatic or fully automatic welding techniques can also be achieved with many custom-built machines, which were specifically designed for grouser reconstruction. With some specialty welding equipment, semi-automatic reconstruction can take place with the grouser shoe still attached to the tractor chain.
The type of steel used in grouser shoes varies by manufacturer. In most cases, the grousers are either high-carbon or alloy steels. Consequently, care must be taken not to fuse too much of the base metal from the grouser shoe or the Grip-Lug into the weld.
Grouser shoes can be reconstructed with Grip-Lug without dismantling the track assembly. Outlined below is a procedure for manually applying Grip-Lug to the grouser shoe.
IMPORTANT PRECAUTIONS
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Do not leave space between worn grouser shoe and Grip-Lug when using semi or fully automatic welding. For manual stick welding, leave a gap of about 1/16” to allow for expansion and contraction.
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A full penetration weld is required to develop maximum strength.
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The likelihood of weld cracking is increased if; the weld current is too high, the weld travel speed is too high, the arc voltage is too high, or the Grip-Lug is cold. Use the proper size electrode and do not use a higher welding current than is necessary for good fusion. Excessive current results in too much alloying elements from the grouser or Grip-Lug to enter the weld. This results in a harder weld, which is more susceptible to crack during cooling.
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Do not weld cold metals. Grouser shoes and Grip-Lug shall be of a uniform temperature and shall be at least 60° F before welding. Pre-heating to 100° to 150° F before welding is recommended.
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To maintain maximum hardness after welding, keep the maximum temperature in the grouser shoe and Grip-Lug bar as low as possible. Before welding the second side, it is recommended to allow the grouser shoe and Grip-Lug bar to completely cool after welding the first side.
PREPARATION
Grouser: Trim each worn grouser with a torch to a uniform height across the width of the shoe. Grind to remove slag and high spots. The trimmed grouser surface shall be clean and smooth.
Grip-Lug Bar: Torch cut or saw cut the Grip-Lug to the required length for the application from the 10’ standard lengths.
WELD PROCESS
| Manual Stick Welding |
A good, high-quality, all-purpose steel electrode is recommended for welding Grip-Lug. A.W.S. E-7018 or E-7028 low hydrogen electrode is suggested for this application and is usable with either DC or AC welding machines. A 5/32” electrode is recommended for the smaller bars, using 160-200 amperes. For the larger Grip-Lug bars, a 3/16” electrode is recommended using 230-280 amps.
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| Semi-Automatic Welding |
Use negative polarity, 3/32” low alloy, high elasticity electrode with a low alloy flux, 450 amperes, D.C. (-) 36 volts. This will weld from 8”-20” per minute depending on the size of the Grip-Lug.
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| Fully-Automatic Welding |
Use negative polarity, 1/8” low alloy, high elasticity electrode with a low alloy flux, 550 amperes, D.C. (-) 33-35 volts. This will weld from 8”-20” per minute depending on the size of the Grip-Lug.
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WELD PROCEDURE
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STEP 1
Start with a grouser shoe that orients the Grip-Lug bar vertically upward. Position the Grip-Lug bar on the worn grouser. (Reminder: For manual stick welding, leave a gap of about 1/16” to allow for expansion and contraction of the metals and penetration.)
Tack weld each end of the Grip-Lug bar to hold it in position. |
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STEP 2
Place a 1” weld bead at each corner to prevent distortion. |
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STEP 3
Before welding the side stringer or root pass, reposition the track so that the newly attached Grip-Lug bar is now in a horizontal position. Start the stringer bead at the center of the Grip-Lug bar and weld toward an outside edge. Next, weld from the opposite edge of the Grip-Lug bar toward the center and start of the first weld. This procedure is known as back-stepping and reduces over-heating. Reposition and repeat this process on the opposite side. |
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STEP 4
Remove weld slag. Starting at the outside edge of the Grip-Lug bar and finishing in the center, apply another weld pass over the stringer beads. Repeat as required. For maximum strength, the finished weld shall completely fill the weld groove of the Grip-Lug, especially at the ends. All weld craters shall be filled. Reposition and repeat this process on the opposite side.
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CAUTION – DO NOT WELD TOO RAPIDLY!
