“Also with Meta-Lax you don’t have to worry about sandblasting. No sandblasting is necessary since the part stays clean,” said Smith. “Therefore, an entire step has been eliminated allowing us to produce more parts while spending less.”

Kanawha Mfg. has increased its productivity and cut down its costs tremendously for material handling and man-hours.

Cost reduction, quality improvements — Kanawha Mfg. has saved approximately 30% compared to the costs of thermal stress relief. ”Since we work on 20 pulverizers per month and save 30 percent by using Meta-Lax, this is a tremendous savings for us and our customers,” said Smith.

Kanawha crew members use the Meta-Lax system daily on the pulverizers, so the fabrications can be welded and machined without cracking. This maintains — if not improves — overall product quality.

Another specific example of consistent cost savings comes from “grizzlies,” the key component to a coal-dumping machine. Grizzlies are very large parts that range up to 30 feet long by 12 feet wide, and weigh up to 20,000 pounds.

In the past Kanawha Mfg. needed to heat each grizzly with torches after welding, to straighten them. Prior to using Meta-Lax during welding, warpage as much as two to three inches occurred, depending on the part size. This would require 16 hours to straighten and would cost approximately $2,500 (combining both man hours and cost of gas to run the torches.) By using the Meta-Lax system Kanawha completely eliminated the reworking step because the parts would only warp about 3/8 of an inch.

Finished product quality has improved because the amount of distortion that results when using the Meta-Lax system is considerably less than when heat-treating.

“Also, in the furnace the material would lose some of its strength causing the part to soften,” Smith recalled. “Meta-Lax doesn’t soften it: it relaxes it.”

This strength loss from thermal stress relieving in the past meant that the shop had to buy oversized and higher-strength material in order to compensate for the distortion, and still meet the customer’s specifications. Now, Kanawha Mfg. can buy the materials at their actual specifications.

Another important fact for us is that we have a machine that can relieve stresses in stainless steel. This represents a nice quality improvement on a lot of power plant parts,” Smith explained. “I’ve been in business 47 years and Meta-Lax is one of the improvements that it is a great advantage.”

Ease of use — Operating the Meta-Lax system has been simple for the fabricators. By comparison, operating a furnace requires constant attention. Although Kanawha Mfg. expected the training to be extensive, it was quick and easy. They have six employees who can run the system for either Meta-Lax stress relief or weld conditioning.

Equipment/Process Details — “Higher quality welds are critical to manufacturers and repair facilities as they seek to produce more sophisticated and higher-quality components,” according to Tom Hebel, vice president, Bonal Technologies, Inc. “Companies that use Meta-Lax to stress-relieve their parts experience less distortion from machining and less premature cracking in service, whereas companies that use Meta-Lax during welding have less cracking, distortion, porosity and shrink line effect at the time of welding, plus the normal stress relief benefits. They may also use one-third of the normal preheat temperature, and can weld easier and faster.”

During the Meta-Lax stress relief process, the operator clamps a force inducer and transducer on the workpiece. The operator then uses instrumentation (usually a computer controlled monitor or a X-Y DataGraph) that measures vibratory amplitudes of the workpiece and determines the harmonic frequency curve. The initial curve represents the “false” harmonic frequency because the metal is stressed. After the force inducer vibrates the workpiece for 15-60 minutes at a frequency corresponding to the sub-harmonic zone of the workpiece, the harmonic frequency is seen to permanently shift. The new curve is the true natural frequency reading, indicative of the metal’s non-stressed (stress-relieved) state.

“Meta-Lax weld conditioning uses the same sub-harmonic technology to vibrate the metal, but it is applied as the liquid weld solidifies. This produces a finer, more uniform grain structure because of the increased accelerated motion at the time of weld solidification. A finer, more uniform weld grain structure is a clear indication of improved mechanical properties,” said Hebel. “Ductility and impact values of welds using the Meta-Lax weld conditioning process increase as much as 400 percent and 75 percent, respectively, over normal welds.”

Results
“We have been extremely impressed with the Meta-Lax technology,” said Smith. “In fact, we have been so impressed that we have invited the local American Welding Society chapter to come in and see how to use Meta-Lax during and after welding.”

Smith said the Meta-Lax system has brought in new business over the years, and indicated that Kanawha Mfg. has been awarded some contracts because it owns the Meta-Lax system. They currently have three units in operation at their Charleston plant.