Lesson 10 - Reliability of Welding Filler Metals

© COPYRIGHT 2000 THE ESAB GROUP, INC. LESSON X 10.9.4.2.2 The test plate must be a material having a minimum tensile strength equal to that of the electrode being tested. The test plate is welded with one weld bead on each side of the plate. This is considered a single-pass weld since each weld will be diluted with the base material. The tensile specimen is cut from the plate, machined to the shape shown in Figure 6, and pulled until fractured. A specimen that breaks in the base plate shall be considered satisfactory. 10.9.4.2.3 The weld beads on the bend specimens are ground or machined smooth and flush with the surface. The specimen is then uniformly bent over a 3/4" radius through an angle of 180° in a suitable jig. The specimen, after bending, may show no crack exceeding 1/8" in length in any direction in the weld metal or the base metal. 10.9.5 Ferrite Test - In austenitic stainless steels, ferrite (as discussed in Lesson V) can be beneficial in reducing cracking in some stainless steel weld metals, while in other envi- ronments, it can reduce corrosion resistance. It can cause brittleness in high temperature service, and can reduce toughness in cryogenic service. For these reasons, the amount of ferrite in austenitic stainless steel weld metal must be established as accurately as pos- sible. Ferrite content can be calculated by using the Schaeffler diagram or the WRC dia- gram as shown in Lesson V, when the chemical analysis of the weld metal is known. It can also be determined by the use of various magnetic sensing instruments. 10.9.5.1 To determine the ferrite level by instrument, a weld pad, as shown in Figure 7, must be made. 10.9.5.2 The copper bars are used as a mold or form to build up the weld metal to the proper height as shown. The welding procedure used in preparing test pad is carefully spelled out in the specification as to welding direction, stops and starts, cleaning and WELD PAD PREPARATION FOR FERRITE TEST Figure 7 WELD DEPOSIT 1/2" TO 5/8" MINIMUM HEIGHT

Lesson 1
The Basics of Arc Welding

Lesson 2
Common Electric
Arc Welding Processes

Lesson 3
Covered Electrodes for Welding
Mild Steels

Lesson 4
Covered Electrodes for Welding Low Alloy Steels

Lesson 5
Welding Filler Metals for Stainless Steels

Lesson 6
Carbon & Low Alloy
Steel Filler Metals -
GMAW,GTAW,SAW

Lesson 7
Flux Cored Arc Electrodes Carbon Low Alloy Steels

Lesson 8
Hardsurfacing Electrodes

Lesson 9
Estimating & Comparing Weld Metal Costs

Lesson 10
Reliability of Welding Filler Metals

Current
Chapter
Table of Contents