Instructions for Welding the "K Series" Adapters{6803} Caterpillar

Track-Type Loader: All

Wheel Loader: All

Introduction

While buckets are being loaded, the base edge assemblies will bend or bow and high stresses are developed in the adapter weld. The most severe stresses are concentrated at the start of the welds on the two strap adapters. The points of stress are at the front of the base edge under the nose of the abrasion and flushmount adapters. Consequently, the application of the welds in these areas must be of the highest quality.

Weld quality is improved with the cleanliness of the metal surfaces. Surfaces must be free of paint, rust, dirt, and moisture. There must be good weld penetration into the adapter and the base edge. Weld quality is also determined by:

• the good fusion between weld passes

• the application of multiple weld passes

• the absence of abrupt starts of the weld

The metallurgical composition of the base edge and the adapters requires preheating.

The use of low hydrogen welding electrodes or welding wire is required to prevent the formation of hydrogen in the weld. Trapped hydrogen can cause cracks to develop in the weld area.

Preheating and slow cooling also allows any trapped hydrogen to escape. This action prevents excessive hardness from developing in areas that are near the weld. This action also reduces stresses that can occur from rapid cooling and weld shrinkage.

Use the following recommended procedure for welding on all adapters for buckets in order to achieve maximum durability.

Welding Material

Use a flux cored wire such as "AWS E71T-1", which is suitable for use in all positions, with hydrogen control and a gas shielding. Use a wire with a diameter of 1.1 mm (0.045 inch) or 1.3 mm (0.052 inch).

Note: If the welds can be applied in a flat horizontal position, you can use a "AWS E70T-5" welding wire.

The wires should have a diffusible hydrogen specification of no more than 5 mL per 100 g of weld deposit. Suppliers have different recommendations for the shielding gas. Generally, the use of pure carbon dioxide is acceptable for most choices of welding wire. However, while pure carbon dioxide improves weld penetration, a mixture of 75 percent argon and 25 percent carbon dioxide is recommended for out-of-position welding. The mixture of argon and carbon dioxide also provides the following benefits: enhanced arc characteristics, less welding spatter and improved bead wetting.

You may use the following low hydrogen stick electrode for all welding: AWS E7018. Since the coating of flux on the stick electrodes will absorb moisture, the coating must be kept dry. Recondition exposed electrodes by heating for 2 hours at a temperature of 260 °C (500 °F). Quick consumption is the major disadvantage of stick electrodes. This results in many stops and starts which can become stress concentrators.

Suppliers of welding wire and electrodes make recommendations about power settings. When possible, use DC reverse polarity to obtain the deepest weld penetration. This setting is called "electrode +".

If greater ductility and superior resistance to cracking are desired especially in colder climates, use the following wire or the equivalent: AWS E81T-Ni1 low nickel wire and AWS E8018-C3 low hydrogen stick electrode. The wire should have a diffusible hydrogen specification of no more than 5 mL per 100 g of weld deposit.

Preparation for Welding

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Protect yourself and others; read and understand this warning. Fumes and gases can be dangerous to your health. Ultraviolet rays from the weld arc can injure eyes and burn skin. Electric shock can kill. Read and understand the manufacturer's instruction and your employer's safety practices. Keep your head out of the fumes. Use ventilation, exhaust at the arc, or both, to keep fumes and gases from your breathing zone and the general area. Wear correct eye, ear and body protection. Do not touch live electric parts. Refer to the American National Standard Z49.1, "Safety in Welding and Cutting" published by the American Welding Society, 2501 N.W. 7th Street, Miami, Florida 33125: OSHA Safety and Health Standards, 29 CFR 1910, available from U.S. Dept. of Labor, Washington D.C. 20210.

Read the instructions from the supplier and understand the instructions from the supplier. Provide fresh air circulation to the welding helmet to avoid any illnesses that can be caused by long-term exposure to the welding fumes. The fresh air circulation will also remove any exhaled carbon dioxide that may be trapped by the welding helmet. Use the following protection when you prepare the surfaces and when you weld on the surfaces: eye protection, ear protection and body protection. Use a welding helmet with a filter plate that is at least Shade-11. Welding helmets that automatically darken eliminate strain in the neck by eliminating the need to flip the welding helmet in order to weld. Also, Welding helmets that automatically darken greatly increase the accuracy in the placement of the electrode.

Before you cut on the bucket or on the weld of the bucket, the temperature of the bucket should be at least 24 °C (75 °F) to 38 °C (100 °F). Do not weld on surfaces that are exposed to fans. Do not weld on surfaces of the bucket that are exposed to natural cool winds. Do not lay the bucket directly on the ground. Do not lay the base edge directly on the ground.

An oxyacetylene torch or an air carbon arc torch may be used to cut an adapter away from the base edge. The air carbon arc torch creates less heat input. This action reduces the tendency for any cracks that may be in the base edge to propagate. The gouged area is also much cleaner after using an air carbon arc torch. This process requires less grinding.

Preparing The Base Edge For the replacement Adapter

Use the following 1 in order to determine the correct size of K-Series adapters that replaces the J-Series.

Replacing a J-Series system with a K-series system does not require a change in the thickness of the base edge.

Illustration 1	g01424112
"Part Numbers for the LDR K System Adapters"

1. Remove the old adapters.

2. After removing the old adapters, grind the surface areas that were gouged by the torch.

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Illustration 2	g01416224
Grinding bevels to side bar (A) 45°

3. Refer to Illustration 2. Remove the corner adapter and grind 45° bevels (A) to the bottom of the side bar. K-series corner adapters will fit under the side bars of the bucket as a direct replacement, but the lifting eyes will need to be removed. The top surface of the strap needs to be ground flat.

Repairing cracks in the base edge

1. Use the following steps in order to repair any cracks in the base edge.

2. Preheat the surface of the base edge to temperatures that are between 149°C and 204 °C (300 °F and 400 °F).

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Illustration 3	g01416227
Cracks that are propagating to blunt height

3. Refer to Illustration 3. Gouge out the crack to full depth. Repairing the cracks, that have propagated all the way to the front blunt height of the base edge, should be considered temporary repairs. These welds should be considered temporary because the cracks will usually reappear in a short time period.

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Illustration 4	g01416231
Gouge out cracks through the base edge.

4. Refer to Illustration 4. Cracks, that go completely through the base edge without propagating to the blunt height must be gouged out from the top and the bottom.

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Illustration 5	g01417672
Cross section view of top weld passes

5. Refer to Illustration 5. Fill the top groove with multiple passes of weld. Extend the weld above the surface of the base edge.

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Illustration 6	g01417678
Cross section view of the bottom of the top weld passes

6. Refer to Illustration 6. Gouge out the bottom of the top repair weld in order to make sure that the top and the bottom welds attain complete fusion. Any space that is left between the top and the bottom welds will develop into a crack.

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Illustration 7	g01417679
Cross section view of the top and bottom weld passes

7. Refer to Illustration 7. Fill in the bottom groove and extend the weld beyond the surface of the base edge.

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Illustration 8	g01417681
Cross section view of the top and bottom weld passes that have been ground flat

8. Refer to Illustration 8. Use a Disc grinder and grind the weldments smooth and flush with the base edge.

Welding the Two strap Adapters To The Base edge

Illustration 9	g02228773
Top view of base edge and adapter

Illustration 10	g02228997
Top view of base edge and adapter (C) Point C (D) Point D

Illustration 11	g02226954
(G) Adapter (H) Adapter to base edge weld (J) Base edge (K) Base edge bevel (L) Adapter bevel (N) First weld pass (P) Second weld pass (R) Third weld pass (S) Fourth weld pass (T) Fifth weld pass (U) Final weld pass (AA) 12 ± 3 mm (0.47 ± 0.12 inch)

Illustration 12	g01418432
View of staggered welds

1. Preheat the adapters and the base edge to temperatures between 150° C (300° F) and 260° C (500° F). Assemble the adapter bevel (L) with hard contact against the base edge bevel (K). Equalize the gaps of the adapter straps. The minimum gap for equalization is 3 mm (0.12 inch) and must be equalized within ± 3 mm (0.12 inch) to the base edge (J). Use the spacers to hold the position while tack welding at mid length in the root of the j-groove on each side of the strap.

   Note: All weld start points, stop points and weld illustrations are general and should be considered identical for both the top and bottom straps. Minor variances can be allowed, depending upon component strap geometry unless otherwise specified on the base edge assembly drawings.

   Note: Factory and production variations in the weld starts and the weld stops for points (C) and (D) is permissible. Stagger the weld starts and stops when possible and consult a facility within process capabilities.

   Note: Weld zones must not exceed the Maximum interpass temperature of 260° C (500° F).

2. Begin the first weld bead at the front of the top strap weld groove root at point (A) or point (E). Weld one continuous pass to the beginning of the rear adapter arc at point (B) or (F). You can continue welding around the rear adapter arc at point (C) to (D). Stagger all of the weld stops and starts as shown in illustrations 11 and 12. Weld stops and starts are not recommended for (C) to (D) as shown in illustration 10.

3. Move to the other side of the adapter (G). Begin the next weld bead at the front of the weld groove root at point (A) or point (E). Weld one continuous pass to the beginning of the rear adapter arc at point B or () point (F). You can continue to weld around the rear adapter arc from point (C) to point (D). Stagger all of the weld stops and starts as shown in illustrations 11 and 12. Weld stops and starts are not recommended from point (C) to point (D) as shown in illustration 11

4. Return to the original weld side and weld another pass. The minimum interpass temperature is 150° C (300° F). The maximum temperature for the interpass is 260° C (500° F).

5. Continue welding alternative sides of the strap until the j-groove at point (A) and point (E) is filled. Do not apply fillet welds at this time.

6. Weld all of the straps as per steps 1 through 5.

7. Turn the base edge (J) over to where the bottom side is facing up. Repeat s the procedures in step 1 to step 4 for the bottom straps.

8. Continue welding alternate sides of the bottom strap until j-groove is filled and fillet welds are complete. Start the first fillet weld pass at point (A) or point (E). All succeeding weld beads should be behind the preceding layer to produce a rounded weld start or finish as shown in illustrations 11 and 12. The fillet bead passes should be applied alternately on each side of the strap from front to back as described in step 2. the final weld pass should be on the previously deposited weld that is near, but not on the weld toe of the base edge (J) .

9. Weld all bottom straps per steps 8 and 11.

10. Turn the back edge over. With the top side up complete the fillet welding of the top straps as per step 8

11. If necessary, grind to blend the starts or stops of the weld and weld toe undercuts. After the initial pass, all weld stops must tie into the previously applied weld ends.

    ReferenceSee Special Instruction, REHS5621, "Instructions for Weld Finish of the "K" Series Adapters Installed on Large Wheel Loader Buckets"

Welding Abrasion And Flushmount Adapters

Illustration 13	g02232654
Top view of base edge and adapter (A) Point A (B) Point B (E) Point E (F) Point F (G) Starter plate

Illustration 14	g02232796
Top view of base edge and adapter (C) Point C (D) Point D

Illustration 15	g02232593
(H) Adapter (J) Base edge (K) Adapter to base edge weld (L) Base edge bevel (M) Location adapter bevel, view is blocked by the adapter to base edge weld

Illustration 16	g02232975
Bottom view of base edge and adapter (P) View of fillet welds

1. Preheat the adapters and the base edge to temperatures between 150° C (300° F) and 260° C (500° F). Assemble the adapter bevel (H) with hard contact against the base edge bevel (L). The top strap should be flush to the base edge top surface. Tack weld at mid length in the root of the weld groove on each side of the strap.

   Note: All weld start points, stop points, and weld illustrations are general and should be considered identical for both the top and bottom straps. Minor variances can be allowed, depending upon component strap geometry unless otherwise specified on the base edge assembly drawings.

   Note: Factory and production variations in the weld starts and stops for points (C) and (D) is permissible. Stagger the weld starts and stops when possible and consult a facility within process capabilities.

   Note: Weld zones must not exceed the Maximum interpass temperature of 260° C (500° F).

2. Tack weld a 10 mm (0.40 inch) thick mild steel starter plate (G) to the leading edge of the base edge (J) at the junction of the upper and lower weld grooves.

3. Begin the first weld on the starter plate (G) at the front of the top strap weld groove root at point (A) or point (E). Weld one continuous pass to the beginning of the rear adapter arc at point (B) or (F). You can continue to weld around the rear adapter from point (C) to point (D). Stagger all weld stops and starts. Weld stops and starts are not recommended from point (C) to point (D) as shown in figure 15

4. Move to the other side of the adapter. Begin the next weld bead on the starter plate at the front of the weld groove root at point (A) or point (E). Weld one continuous pass to the beginning of the rear adapter arc at point (B) or point (F). You can continue to weld around the rear adapter from point (C) to point (D). Stagger all weld stops and starts. Weld stops and starts are not recommended from point (C) to point (D) as shown in figure 15

5. Return to the original weld side and weld another pass. The minimum interpass temperature is 150° C (300° F). The maximum interpass temperature is 260° C (500° F).

6. Continue welding alternative sides of the strap until both welds are complete. Refer to illustration 16

7. Weld all adapter top straps following steps 1 through 6.

8. Turn the base edge (J) over to where the bottom side is facing up. Arc-air gouge through the starter plates until the upper welds are exposed.

9. Fill the lower weld groove by starting the welds from alternate ends of the groove. At completion, the lower weld should be flush with the bottom of the base edge (J). This area should also be blended with the ends of the upper welds.

10. Weld all bottom grooves as directed in steps 7 through 9.

11. If necessary, grind to blend the starts or stops of the weld and weld toe undercuts. After the initial pass, all weld stops must tie into the previously applied weld ends.