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Exhaust System Components  GMT Inc. offers a unique product for every exhaust application. Stainless steel wool shapes are used for sound attenuation and basalt/glass wool retention in automotive mufflers. A layer of stainless steel wool between the perforated pipe and the basalt/glass wool packing enhances the performance and life span of these mufflers. All GMT exhaust products start with the same alloy type AISI 434 stainless steel wool, in grades Fine (60 micron), Medium (80 micron), and Coarse (120 micron). Stainless steel wool products withstand temperatures in excess of 700°C, exhaust acids and high vibration. BENEFITS: The performance of stainless steel wool in automotive mufflers has proven itself in thousands of applications. The properties of resilience, sound attenuation, durability and integrity are unavailable in any single alternative material. Furnace tests show that stainless steel wool will withstand sustained temperatures of 700°C and peak temperatures of 800° C for up to 10 minutes without damage or degradation. MATERIAL: Alloy type AISI 434 stainless steel. CHEMISTRY: C (Carbon) 0.12% max. Si (Silicon) 1.0% max. Mn (Manganese) 1.0% max. S (Sulfur) 0.03% max. P (Phosphorous) 0.04% max. Cr (Chromium) 16.0 - 18.0% max. Mo (Molybdenum) 1.25% max. Fe (Iron) remainder FIBER SIZES: Fibers typically used are in the range of 60 - 130 microns (0.0024" - 0 .0051"). FORMAT: Available in common 4" rolls, needled batt up to 1.52 meters (60 inches) wide, Metrix Muffler Tubes, (MMT™ brand), or die cut shapes. Also available in our exclusive METRIX ™ stainless steel wool textiles in many configurations. TOLERANCES: Weight of Stainless Steel tubes and die cut shapes to +/- 10%. All other products to weight tolerance of +/- 15% or as specified. Fiber width tolerances as required in material specifications.  COMMON REELS:  The simplest form of stainless steel wool is a continuous roving, 4 inches wide on reels. This product meets all of the physical demands for exhaust applications, but is presented in a basic form requiring the muffler manufacturer to do all of the processing and assembly. METRIX TYPE NR: Type NR (or Needled Roving) is a needle punched version of the continuous roving. The needle roving allows specification of width, density, and basis weight of the material. Type NR can be die cut into shapes or built up in layers to form blocks of packing, and can be spot welded in place. Type NR is shipped in uniform width continuous rolls, in pieces cut to length, or as die cut shapes, as specified, up to 10” wide. Benefits: Using Type NR material reduces assembly labor and improves the consistency of products, because the weight of every piece of equal size will have the same weight, thickness, and porosity. Metrix Type CL: Type CL (or Cross Layered needle batt) is also a needle punched version of the continuous roving. Type CL is made by needle punching together layers of fibers running in alternating directions. This forms large blankets of strong, porous, flexible medium. This product is appropriate where large scale wraps, packs or die cut shapes are required. Benefits: Type CL offers the same benefits as Type NR, and can be manufactured in much larger sizes up to 60” wide by continuous length, in thickness’ from ¼” to 1”. Type CL exhibits excellent isotropic strength (tear resistance in all directions) and can be die cut into more intricate shapes than Type CL without coming apart. MMT™: Metrix Muffler Tubes (MMT) are the most refined of the exhaust components. MMT are made by forming Type NR material into a seamless tube with uniform physical properties. They are available in diameter from 1-3/4” ID and up, with almost any wall thickness and lengths up to 8 feet. Benefits: The most distinguishing characteristic of the MMT is the ease of manufacture into the muffler. The part is simply taken out of the shipping carton, popped open, and installed on the perforated or louvered pipe. This product is appropriate where consistency and low installation labor are important. Metrix Muffler Tubes offer the same performance benefits as Type NR. For muffler packing where there is a temperature environment in excess of 700°C, exhaust acids and high vibration. Also used to retain and insulate other packing materials in high performance exhaust applications. APPLICATION NOTES: The recommended packing density in a muffler body is 100 g/L minimum, for normal applications. The fiber length is continuous and withstands normal alkaline and acidic conditions. GMT's value-added exhaust products can improve performance while saving manufacturing time, space, and overall costs. Call our applications experts today to find out how METRIX ™ and MMT™ can improve your design- and your bottom line.

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