Nondestructive Testing service providers

  Failure investigation often   uncovers facts  that lead to changes in design, manufacturing, or operating practice, which will eliminate similar failures in the future. Failures of insignificant parts can also lead to advances in knowledge and should be done objectively, as with a large structure. The following four areas of interest should be investigated to determine the cause of weld failure or weld defects and the interplay of factors involved: Initial observation . The detailed study by visual inspection should be made at the failure site as quickly as Photographs should be taken, preferably in color, of all parts, structures, failure surfaces, fracture texture appearance, final location of component debris, and all other factors.   Background data . All information concerning specifications, drawings, component design, fabrication methods, welding procedures, weld schedules, repairs in and during manufacturing and in service, maintenance, and service use. Att...

  Welding of Stainless Steels: General Concepts: Stainless steels, resumed here in a general way, are defined as steel alloys, where the  chromium content  ranges from  10.5% to 30%.  There are five distinct types of stainless steel: Ferritic stainless steel: Contains from  10.5 to 30% chromium , is low in carbon, with some alloys containing major amounts of molybdenum, columbium and titanium. Austenitic stainless steel: Contains from  16% to 26% chromium  and up to 35% nickel and have very low carbon content. Some of these steels are also alloyed with a minor amount of molybdenum, columbium and titanium. Martensitic alloy steel: Contains from  12% to 17% chromium  and up to 4% nickel and 0.1% to 1.0% carbon. Some alloys will also have minor additions of molybdenum, vanadium, columbium, aluminum and copper. Duplex stainless alloys: Contain  18% to 28% chromium , 2.5% to 7.5% nickel and low carbon contents. Some of the alloys will al...