A Root Cause Analysis of Catastrophic Failure of Industrial Discharge Hopper Pipe | Chapter 8 | Engineering Research: Perspectives on Recent Advances Vol. 3

Several failures of the industrial pipes have been reported in the past and most of them are due to Stress Corrosion Cracking (SCC), sensitization and hydrogen embrittlement. Stress Corrosion Cracking is a delayed failure where corrosion environments such as condensed water, ammonia solutions, moist air, and solutions containing chlorides and nitrides play a major role. This work presents a detailed investigation and root cause analysis of the catastrophic failure of an industrial discharge hopper pipe. The hopper pipe investigated in the present work is made of austenitic stainless steel, 316 grade, a commonly used grade for valves, pipes and heat exchanger tubes. The pipe fractured in the transverse direction, leading to the failure of the discharge pipe. Visual inspection, dye penetrant test, chemical analysis, microstructural analysis, and fractography analysis were carried out on the failed part and it was concluded that stress corrosion cracking led to the failure of the hopper pipe. The pipe constantly being under exposure to industrial water and the presence of chlorine content in it made it susceptible to stress corrosion cracking. Transgranular fracture was clearly observed in the microstructure of the failed sample and spot EDX at the fracture location confirmed the presence of chlorine content. This indicates that the pipe has been subjected to corrosion because of service conditions/environment and any of those minor cracks would have opened up with the continued service operation, had the major transverse fracture not taken place. Further, fractography showed striations indicating fatigue loading. The work concluded that stress corrosion cracking was the root cause of failure. Cathodic protection or suitable polymer coating should be considered as the preventive measures to avoid stress corrosion cracking in future.

 

Author (s) Details

 

S. Rajole
Department of Mechanical Engineering, School of Engineering, Central University of Karnataka, Kalburgi 585367, India.

 

P. R. Sondar
Department of Metallurgical and Materials Engineering, National Institute of Technology Karnataka, Surathkal 575025, India.

 

S. Hiremath
Department of Mechatronics Engineering, Manipal Institute of Technology, Manipal 576104, India.

 

K. S Ravishankar
Department of Metallurgical and Materials Engineering, National Institute of Technology Karnataka, Surathkal 575025, India.

 

Please see the book here:- https://doi.org/10.9734/bpi/erpra/v3/3965

Weldability Studies of Novel Chromium Free Electrodes with Austenitic Grade Stainless Steels| Chapter 4 | New Approaches in Engineering Research Vol. 2

 Because of their strong corrosion resistance and good mechanical qualities, stainless steels are commonly used materials. Welding of stainless steel, on the other hand, produces hexavalent chromium vapours, which are hazardous to welders and operators in the welding area. A unique filler material has been created to minimise these hexavalent vapours, as suggested by the Occupational Safety and Health Administration. The primary goal of this chapter is to explore the development of chromium-free filler materials for welding austenitic stainless steel grades and to study the weldments' mechanical and corrosion resistance. This case study contains filler material development as well as microstructure. characterisation, analysis of the effect of welding factors such as current, gas flow rate, and root gap on weldment qualities such as ultimate tensile strength, impact strength, hardness, and corrosion resistance, and Taguchi and Response Surface Methodology optimization of welding parameters (RSM). For an optimal current value of 130A, 11.79litres/min gas flow rate, and 2.33mm root gap, the weldments showed a maximum tensile strength of 324 MPa, a maximum hardness of 209VHN, and a minimum corrosion rate of 1.575e-004mils/year.

Author (s) Details

Koushik Kosanam
Department of Manufacturing Systems Engineering and Management, California State University, Northridge, US.

Dr. J. R. Nataraj
Department of Mechanical, RV College of Engineering, india.

View Book :- https://stm.bookpi.org/NAER-V2/article/view/2118

Current Trends in Diffusion Bonding of a Titanium Alloy to a Stainless Steel with an Aluminium Alloy Interlayer | Chapter 10 | Advanced Aspects of Engineering Research Vol. 4

 Diffusion bonding, as opposed to edge joining through welding or other metal joining techniques, is the method of joining identical or dissimilar materials at the interface. It's a solid-state welding procedure that involves soaking the surfaces to be joined at a certain temperature, bonding time, and load. To prevent interface reactions that can cause corrosion, this is usually done under vacuum or in an inert atmosphere. Diffusion bonding is a method of moving atoms from one surface to another and breaking aspirates on bonding or diff surfaces by utilising clusters of atoms from related and dissimilar metals. Diffusion bonding was performed under various temperature, bonding time, and load conditions. Since diffusion bonding is an atomic transfer between the surfaces, these parameters are optimised for better bond strength, and the bonded specimens are examined for micro structural changes and bond strength. The micro hardness test is used to determine the strength of the bond at the interface. Inserting another material as an interlayer at the interface will increase the bond's strength. The base metal titanium is bonded to stainless steel with an interlayer of aluminium.

Author (s) Details

K. Chandrappa
Department of Mechanical Engineering, Siddaganga Institute of Technology, Tumkur-572103, Karnataka, India.

Amit Kumar
Department of Mechanical Engineering, Siddaganga Institute of Technology, Tumkur-572103, Karnataka, India.

Kumar Shubham
Department of Mechanical Engineering, Siddaganga Institute of Technology, Tumkur-572103, Karnataka, India.

View Book :- https://stm.bookpi.org/AAER-V4/article/view/643