Improved P/M stainless steel exhaust flanges based on innovative design concepts

摘要

Powder metal (P/M) stainless steel exhaust flanges have been qualified for a number of passenger cars and trucks in recent years. These flanges are currently being produced in high volumes to supply those vehicles. The requirements for these applications will continue to change over time as federal and state governmental mandates for improved emissions become effective. Lower leak rate limits, higher engine operating temperatures, and extended service life for components, are among the consequences of the search for improved emissions. The P/M process offers a high degree of flexibility with product design and related materials development, thus being able to meet these challenges. P/M stainless steel exhaust flanges' performance can be enhanced by 1. optimal design using finite element analysis and 2. modifying alloy compositions to improve strength. Hot Vibration Water Quench Tests have shown that significantly lower leak rates can be exhibited by enhanced P/M flanges versus wrought. The P/M flanges show superior flatness, and meet thermal, mechanical and oxidation/corrosion resistance requirements. These flanges offer the exhaust system design engineer virtually no constraints for packaging flanges in a confined area, and the opportunity to have flanges that have service life after field repairs.