1、 WORLDWIDE ENGINEERING STANDARDS Material Specification GMW16977 Acoustic Absorbing Material for Exhaust Applications Copyright 2013 General Motors Company All Rights Reserved June 2013 Page 1 of 11 1 Scope This specification defines fibrous glass materials used as acoustic-absorbing and thermal ins
2、ulation media primarily used in automotive exhaust applications. The specification includes properties, both chemical and physical, required for moderate-, intermediate-, and high-temperature applications in exhaust systems. 1.1 Material Description. This specification describes three (3) types of f
3、ibrous glass materials typically used in silencer components of exhaust systems. The materials are classified as Type 1 for moderate-temperature applications, Type 2 for high-temperature applications and Type 3 for intermediate-temperature applications. These materials are utilized in environments w
4、here they will be exposed to hot exhaust gases, but the primary flow of the exhaust gasses is not normally through the mass of glass fibers. The fibers provide a mechanism for the dissipation of acoustic energy as well as providing thermal insulation around the path of the exhaust gases. 1.1.1 Mater
5、ial Identification. Type 1, or moderate-temperature applications, are those applications where the fibrous material itself will achieve continuous operating temperatures of 730 C or intermittent temperatures as high as 825 C for up to 2 h. Thus, this material should be suitable for virtually all app
6、lications toward the rear of the exhaust system and many applications near the catalytic converter, either alone or in combination with a high-temperature material adjacent to the perforated tube. Type 2, or high temperature applications, are those applications where the fibrous material itself will
7、 achieve continuous operating temperatures of 825 C or intermittent temperatures as high as 900 C for up to 2 h. This material is suitable for virtually all applications toward the rear of the exhaust system and near the catalytic converter. Type 3, or intermediate-temperature applications, are thos
8、e applications where the fibrous material itself will achieve continuous operating temperatures of 810 C or intermittent temperatures as high as 890 C for up to 2 h. This material is suitable for virtually all applications toward the rear of the exhaust system and most applications near the catalyti
9、c converter. Note: For many silencer applications in continuous operation, the glass temperature adjacent to the perforation tube is 50 C below the exhaust gas temperature. For cyclic operations of a few minutes duration, this temperature differential is larger. 1.2 Symbols. Not applicable. 1.3 Typi
10、cal Applications. These materials are typically used in exhaust systems where thermal insulation and/or acoustic attenuation are required. The choice of materials is primarily determined by the maximum operating temperature that the material will achieve. 1.4 Remarks. Not applicable. 2 References No
11、te: Only the latest approved standards are applicable unless otherwise specified. 2.1 External Standards/Specifications. ASTM C336 ASTM E1050 2.2 GM Standards/Specifications. GMW3059 GMW3205 Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo re
12、production or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW16977 Copyright 2013 General Motors Company All Rights Reserved June 2013 Page 2 of 11 2.3 Additional References. TMC003 Material Safety Data Sheet guidance documents (available at ). 3 Requirements
13、 3.1 Performance Requirements. The Type 1 moderate-temperature fiberglass rovings (containing about 4000 individual filaments), Type 2 high-temperature fiberglass rovings (containing about 1850 individual filaments), and the Type 3 intermediate-temperature fiberglass rovings (containing about 4000 i
14、ndividual filaments) are put through a process (texturizing) which separates them into individual filaments and groups of a few dozen filaments before they are placed into a silencer. The ability to separate the strand into filaments is required for the silencer to achieve the desired acoustic perfo
15、rmance. 3.2 Chemical Requirements. The compositions of the three (3) types of glasses are shown in Table 1. Table 1: Composition of Glass Fibers in Weight Percent (wt%) Chemical Constituent Type 1 Moderate Temperature Type 2 High Temperature Type 3 Intermediate Temperature SiO2 55 to 65 62 to 69 62
16、to 69 CaO 18 to 25 720 C as determined by ASTM C336. The Type 2 high-temperature glass must have an annealing point 810 C as determined by ASTM C336. The Type 3 intermediate-temperature glass must have an annealing point 790 C as determined by ASTM C336. 3.2.3 Phase Stability Requirements. The Type
17、1 moderate-temperature material must remain amorphous when heat-treated for 24 h at a temperature of 860 C. The Type 2 high-temperature material must remain amorphous when heat-treated for 24 h at a temperature of 925 C. The Type 3 intermediate-temperature material must remain amorphous when heat-tr
18、eated for 24 h at 920 C. 3.2.4 Requirements for Preforms and Bag Materials. For initial material qualification approval only, the bag or preform shall achieve a rating of six (6) minimum when tested to GMW3205 Code C modified at a minimum temperature of 400 C. 3.2.4.1 Requirements for Low Emission P
19、reforms. The Low Emission Preforms (also known as Preform LE) must present a mean Loss on Ignition (LOI) of 0.6% when tested according to the Loss on Ignition Test described in Appendix B. 3.3 Transmission Loss. The minimum transmission loss of a 100 mm thick sample of this material at various packi
20、ng densities after texturizing is shown in Table 2. The absorption coefficient is measured according ASTM E1050. Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE E
21、NGINEERING STANDARDS GMW16977 Copyright 2013 General Motors Company All Rights Reserved June 2013 Page 3 of 11 Table 2: Minimum Linear Absorption Coefficient of Absorptive Materials Frequency (Hz) 100 g/L 150 g/L 200 g/L 200 0.3 0.4 0.5 400 0.8 0.8 0.8 600 0.9 0.8 0.75 800 0.9 0.85 0.8 4 Manufacturi
22、ng Process Not applicable. 5 Rules and Regulations 5.1 Legal Regulations. All materials must satisfy applicable laws, rules, regulations and recommendations valid in the country of usage. 5.2 Language. In the event of conflict between the English and domestic language, the English language shall tak
23、e precedence. 5.3 Inspection and Rejection. Samples of components or materials released to a GM material specification shall be tested for conformity with the requirements of this material specification and approved by the responsible Engineering department prior to commencement of delivery of bulk
24、supplies. A new approval must be received for any changes, e.g., properties, manufacturing process, location of manufacture, etc. If not otherwise agreed, all testing and documentation normally required for initial release must be completed. It is the responsibility of the supplier to inform the cus
25、tomer in a timely manner, without solicitation, and to include documentation of all modifications of materials and/or processes and to apply for a new release. If not otherwise agreed, all release tests shall be repeated and documented by the supplier prior to commencement of delivery of non-conform
26、ing bulk supplies. In individual cases, a shorter test can be agreed to between the responsible Engineering department and the supplier. 5.4 Material Safety Data Sheets/Safety Data Sheets (MSDS/SDS). For new product submissions, or when a change in chemical composition of an existing product has occ
27、urred, a complete copy of the Material Safety Data Sheet/Safety Data Sheet must be submitted in compliance with the Globally Harmonized System of Classification and Labeling of Chemicals (GHS) requirements or other country-specific MSDS/SDS requirements. In addition, product MSDS/SDS submissions mus
28、t be in compliance with specific country General Motors TMC003 Material Safety Data Sheet/Safety Data Sheet guidance documents where available. 5.5 All materials supplied to this standard must comply with the requirements of GMW3059, Restricted and Reportable Substances for Parts. 6 Approved Sources
29、 Materials supplied to this specification must be approved by General Motors. A list of approved materials can be found in MATSPC. This GM Material File is provided to third parties to reduce redundant testing of materials. If approved material already listed is used, the part supplier can use GM Ma
30、terial File reference for Production Part Approval Process (PPAP) material approval. If the decision is made to use a not yet approved material, contact the appropriate GM Materials Engineer for details on the approval process. The material approval process must be completed prior to PPAP start date
31、 of the part supplied to General Motors. 7 Notes 7.1 Glossary. MATSPC: Global repository of GM approved materials for corresponding GM Engineering Standards. Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitte
32、d without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW16977 Copyright 2013 General Motors Company All Rights Reserved June 2013 Page 4 of 11 7.2 Acronyms, Abbreviations, and Symbols. ASTM ASTM International FWL Fiber Weight Loss GHS Globally Harmonized System of Classification and Lab
33、eling of Chemicals GSSLT Global Subsystem Leadership Team H2SO4 Sulfuric Acid HCl Hydrochloric Acid KCl Potassium Chloride LE Low Emission LOI Loss On Ignition MSDS Material Safety Data Sheet (NH4)2SO4) Ammonium Sulfate (NH4)(NO3) Ammonium Nitrate PPAP Production Part Approval Process SDS Safety Dat
34、a Sheet WB Balance Weight WC Crucible Weight WS Stabilized Weight Wt% Weight Percent 8 Coding System This standard shall be referenced in other documents, drawings, etc., as follows: Material per GMW16977 9 Release and Revisions This standard was originated in May 2013. It was first approved by the
35、Textiles/Trim Materials Global Subsystem Leadership Team (GSSLT) in June 2013. It was first published in June 2013. Issue Publication Date Description (Organization) 1 JUN 2013 Initial publication. Cross Reference of Replaced Material Coding GMW16977 Material Codes Formerly Identified As Type 1 GMN1
36、0027 Type 1 (GMNA) Type 2 GMN10027 Type 2 (GMNA) Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW16977 Copyright 2013 General Motors Comp
37、any All Rights Reserved June 2013 Page 5 of 11 Appendix A A1 Simulated Exhaust Fluid Durability Test Procedure A1.1 Safety. This durability test procedure may involve hazardous materials, operations, and equipment. This test procedure does not intend to address all the safety problems associated wit
38、h its use. It is the responsibility of the user of this test procedure to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. A1.2 Preparing the Samples. Equipment: Glass fibers Non-powdered gloves Anti-static containers with lids
39、, or equivalent Scissors Dry glove box Procedure: 1. Put on non-powdered vinyl, latex, or nitrile gloves. 2. Cut sample fibers to a length of approximately 1.0 cm into an anti-static plastic container. Caution: Do not cut glove fingers into the sample. 3. Place lid loosely on container. Do not seal.
40、 Place container into dry glove box exchange chamber. A1.3 Transferring Samples to Glove Box. Equipment: Vacuum pump Glove box Dry nitrogen Procedure: 1. Ensure that the glove box exchange chamber inner and outer doors are closed. 2. Turn on vacuum pump and open the valve to the exchange chamber. 3.
41、 Pump the chamber until the vacuum level is -26 psi. 4. Close the vacuum valve to the exchange chamber. 5. Open the nitrogen valve to the exchange chamber slowly until the pressure begins to increase at approximately 5 psi/minute. 6. When the pressure in the exchange chamber reaches atmospheric pres
42、sure, open the inside door of the exchange chamber and place the samples into the glove box. 7. Remove the lids from the top of the containers to expose the fibers to the dry atmosphere. Let the fibers equilibrate with the glove box for at least 4 h, preferably overnight. A1.4 Weighing the Samples.
43、Equipment: Analytical balance: 0.1 mg Brush Glass vials Ceramic crucibles Forceps Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW16977 C
44、opyright 2013 General Motors Company All Rights Reserved June 2013 Page 6 of 11 Procedure: Note: During weighing, it is important that no object to be weighed is touched with the gloves, as static charges will be transferred and adversely affect the weighing. 1. Clean the surface of the pan so that
45、it is free of fibers. 2. Using forceps, place a glass vial on the balance and tare the balance. 3. Using forceps, weigh 1.000 g 0.001 g of chopped fibers into the vial. Note: If the glass is highly soluble, the sample size should be reduced to 0.2500 g 0.0005 g. If the larger sample size is used wit
46、h a highly soluble glass, the test solution will become saturated and dissolution will be hindered. The final mass loss measurement would be artificially low. 4. Brush away any fibers that were dropped on the pan or outside the vial. 5. After the balance is stabilized, record the data stabilized wei
47、ght (WS). 6. Using forceps, remove the sample from the pan and record the empty balance weight (WB). This is the empty bottle weight. 7. Tare the scale and weigh the bottle with the sample. Record this weight (WB + WS). This is the empty bottle plus sample weight. The weight obtained in Step 5 shoul
48、d differ from the difference of the weights obtained in Steps 6 and 7 by 0.0005 g. If the difference is greater, reweigh the sample. A1.5 Weighing the Crucibles. Equipment: Ceramic crucibles Forceps Analytical balance: 0.1 mg Procedure: 1. Tare the balance and, using forceps, weigh one crucible for
49、each sample. 2. Record the crucible weights (WC). A1.6 Solution. A1.6.1 Preparing the Solution. Equipment. Carboy ( 5 L capacity) Concentrated sulfuric acid (H2SO4) Concentrated hydrochloric acid (HCl) 6 N hydrochloric acid (HCl) Potassium chloride (KCl) Ammonium sulfate (NH4)2SO4) Ammonium nitrate (NH4)(NO3) Balance: Accurate
