Checking Fixtures

Checking Fixtures

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Description: Checking fixtures were welded out of tubular components of 1020 hot rolled steel, primarily consisting of a row of 2 x 6 tubes standing on edge, welded to the edges of 2 x 4 tubes, with a 1-inch thick plate welded to the edge of those tubes. The overall length was 16-feet long. Further, after welding the checking fixtures were machined which included milling and drilling of about 200 holes.

Normal Performance: Distortion from welding averaged 0.375-inch. Straightening after welding was always needed and the tolerance for straightening was 0.100-inch flatness. Distortion from machining averaged 0.010-inch.

Performance After Meta-Lax Weld Conditioning: Checking fixtures were welded using Meta-Lax during welding. Distortion from welding varied between 0.050 to 0.070-inch (81-87% less than normal). This distortion control eliminated the need for straightening. Distortion following machining was 0.0015-inch (85% less than normal).

Longeron

Description: Longerons for U.S. bombers, which connect the cockpit to the fuselage, consisted of forgings made out of 7075 aluminum and measured 8-inch x 18-inch x 18-feet. The finished product required several extensive machining steps. Forgings started at 1,665 lbs. and finished around 600 lbs. The tolerance over the length was 0.125-inch flatness.

Normal Performance: Normal distortion always exceeded the desired tolerance to the point that special approval was given to accept longerons with an overall flatness distortion that was less than 0.200-inch. Even with the special approval, the scrap rate was around 90 percent.

Performance After Meta-Lax Stress Relief: Meta-Lax stress relief was applied to one longeron (before any machining) as a trial. The Meta-Lax treated longeron was machined to an overall flatness of 0.087-inch (42% better than their previous best).

Die Holder Blocks

Description: Die holder blocks used in die casting machinery develop cracks and need weld repair on a regular basis. The holder blocks are 5 x 18 x 24-inches.

Normal Performance: Following welding normal distortion would vary between 0.020 to 0.030-inch.

Performance After Meta-Lax Weld Conditioning: Meta-Lax Weld Conditioning was added to the welding process. Distortion from the holder blocks were held to 0.005-inch (75-87% less distortion than normal).

Bottom Slide

Description: Cast iron slides used in milling machines, with approximate size being 6 x 30 x 72-inches, included a heat treat stress relief before final grinding to achieve tolerance.

Normal Performance: Bottom slides were normally ground to a flatness of between 150-200-millionths-inch, or 0.000150 to 0.000200-inch.

Performance After Meta-Lax Stress Relief: Meta-Lax stress relief was applied in place of heat treat stress relief before grinding. Bottom slides were ground to 20-millionths-inch, 0.000020-inch (87-90% less distortion than normal).

Die Preforms

Description: 125 tungsten carbide die performs, 4-inches thick, were wire EDM.

Normal Performance: Of the first group of 15 performs to be wire EDM, eight performs cracked and had to be scrapped.

Performance After Meta-Lax Stress Relief: Meta-Lax stress relief was applied in batches of several performs at a time before wire EDM. The result was that Meta-Lax processing eliminated cracking throughout the rest of the program. A 50+ scrap rate was eliminated.

Fairwater Planes

Description: A fairwater plane is the horizontal fin towards the top part of a submarine. It is made out of HY80 steel and is hollow with tar like material filling the inside. Cracking frequently occurs and requires weld repair. The normal repair procedure required scarfing, preheating, and welding the cracked area. Each repair cycle would normally take 1-2 shifts plus 24 hours for cool-down.

Normal Performance: Reoccurring cracking within 24 hours of repair welding was common. This reoccurrence of the cracking after weld repairing was severe ranging between 20 to 45 times per fairwater plane.

Performance After Meta-Lax Weld Conditioning: Meta-Lax Weld Conditioning was added to the weld procedure on two fairwater planes for testing. The first one had already been welded 40 times. MLWC was applied and they did not use any preheat. After the 24 hour cool-down the fairwater plane was inspected and no cracks were found. MLWC was applied to a second fairwater which had just not yet been repair welded. Following the first weld repair there was a small crack identified. Following the second weld repair with using MLWC there were no cracks found.

Crankshafts

Description: High performance racing crankshafts are considered by many experts as one of the weakest links in a race engine. Giving the cranks a heat treat stress relief is typical prior to machining.
Normal Performance: Normally the cranks would break with an average of 10 races on the crank.
Performance After Meta-Lax Stress Relief: Meta-Lax stress relief was used in place of heat treat stress relief. The result was that the crankshafts were averaging 30 races before breakage (200% longer fatigue life).

Excavator Buckets

Description: Excavating buckets used in the mining industry frequently experience fatigue cracks specifically in the welded area that hold the teeth in place. This would require frequent repairs.
Normal Performance: Normally the welds around the teeth would crack within six weeks in service and require repair.
Performance After Meta-Lax Weld Conditioning: Meta-Lax Weld Conditioning was added to the welding procedure. The buckets now last 6 to 10 months before the same repair is needed (200% to 400% fatigue life improvement).