CONTROL GP-UNPROGRAMMED 1512106 - Caterpillar

Preheating
Preheating the piece parts before welding is an effective method to reduce cooling rates of the weld and Heat Affected Zone (HAZ). Preheating also controls distortion, residual stress, and arc input required for weld deposit. Preheating prevents cracking in hardenable steels and increases the HAZ width. Without preheat, the HAZ can result in a brittle metallurgical structure. Track shoe grouser trimming provides preheat for the pad. The replacement grouser bar requires preheat also. The preheat temperature for alloy or high carbon steel should be 149 °C (300 °F).Types of Equipment
Illustration 5 g02375823
Typical submerged arc grouser welding in process.
Several types of welding equipment are used for grouser bar fabrication. Mechanized equipment has stations for grouser bar trimming, welding, and replacement bar. One mechanized grouser bar welder is the WTC model CG-3 Grouser Welder.Grouser Bar
Replacement grouser bars should be made from 10B35 material. The material will assure a heat treat of 50 Rc hardness for the grouser countour. Core hardness should average 47 Rc. Grouser bars must be available in cut-to-length sizes and in non-heat treated 6 m (20.0 ft) lengths. This quantity provides for good field performance.Welding Parameters
Table 3
Mechanized Welding Equipment
Process Sub Arc - Tiny Twin Sub Arc - Single Wire
Parameters Wire Type
Wire Lincoln L-60 5/64 diameter Lincoln L-60 1/8 diameter
Flux Lincoln 760 or Lincoln 780 Lincoln 760 or Lincoln 780
Wire Feed Speed 250 to 350 I.P.M. 90 to 115 I.P.M.
Amperage 1000 to 1400 700 to 800
Voltage 35 to 40 35 to 40
Stickout 31.8 mm (1.25 inch) 31.8 mm (1.25 inch)
Polarity Reverse Reverse
Travel Speed 15 to 25 I.P.M. 10 to 15 I.P.M.
Table 4
Semi-Automatic Welding Equipment
Process Flux Cored Sub Arc
Parameters Wire Type
Wire Lincoln NS-3M 3/32 Lincoln L-60 5/64 diameter
Flux/Gas Shielding -- Lincoln 760 or 780
Wire Feed Speed 230 to 275 I.P.M. 240 to 265 I.P.M.
Amperage 400 to 450 450 to 500
Voltage 31 to 32 34 to 38
Stickout 69.9 mm (2.75 inch) 28.58 mm (1.125 inch)
Polarity Reverse Reverse
Travel Speed 16 to 22 I.P.M. 12 to 15 I.P.M.
No. of Passes 1 to 2 1 to 2 The recommended welding parameters are a guide to fabrication. During grouser bar welding, adjustments may be made to maintain weld quality. The consumables are examples used by Caterpilar dealers. All welding consumables meet American Welding Soceity specifications.Welding Procedure (Shoes Removed)
With mechanized grouser welders, track shoes are removed from the chain assembly and then cleaned and trimmed.
Not necessary to tack weld grouser bars into position when using mechanized welding equipment capable of hydraulic clamping. When no clamping mechanism is available, the replacement grouser bars must be tack welded into place using E7018 1/8 diameter electrode.
Track shoe/replacement bar should be preheated to 149 °C (300 °F). No welding should occur if the temperature falls below 65 °C (149 °F).
Use the recommended welding consumables and parameters outlined on Table 3 and Table 4.
Avoid gaps between the track shoe and grouser bar. Weld penetration can cause burn-through. When required, fill the gap using E7018 electrode or a multi-pass weld.
Cracking can occur if current is too high or