CAUSES OF MICRO-FLAWS IN HIGH-STRENGTH WELD METALS, THEIR EFFECTS, AND METHODS OF ELIMINATING THEM. Final Report

Technical Report · Mon Jul 31 04:00:00 EDT 1961

OSTI ID:4779290

Randall, M D; Monroe, R E; Rieppel, P J

Research was conducted to study the causes of microdefects in high- strength steel welds, determine the effects of such microdefects on weldment performance, and determine methods for eliminating such defects. Welds were deposited in air-melted and vacuum-melted 300M steel by the inert-gas-shielded, W- arc and electron-beam welding processes. Tension, bend, and impact tests were made of these weldments and base plate. Metallographic examination and supplementary studies were made. It was determined that micro-defects can cause low-load failure. These defects occur at temperatures near the alloy solidus temperature and are chemistry controlled. Microsegregation of S, P, and Si occurs in these welds, and Si lowers elevated-temperature ductility and promotes hot cracking, Grain-boundary liquation of heat-affected zones occurs. (auth) 52O Visual inspection, dimensional inspection and ultrasonic testing were carried out on two Mn--Mo sheets. The surface condition after descaling was satisfactory for sheets of the thickness considered. With reference to the nominal thickness, the dimensions noted showed maximum variations of 2%. The ultrasonic check detected spot defects located at mid-thickness and of light character only. (M.C.G.)

• Research Organization: Battelle Memorial Inst., Columbus, Ohio
• NSA Number: NSA-17-000519
• OSTI ID: 4779290
• Report Number(s): WAL-TR-642.4/1
• Country of Publication: United States
• Language: English

Related Subjects

AIR
CRACKS
DEFECTS
ELECTRIC ARCS
ELECTRON BEAMS
FAILURES
GRAIN BOUNDARIES
HIGH TEMPERATURE
INERT GASES
MECHANICAL PROPERTIES
MELTING
METALLOGRAPHY
METALS, CERAMICS, AND OTHER MATERIALS
PHOSPHORUS
PRECIPITATION
SILICON
STEELS
SULFUR
TENSILE PROPERTIES
TUNGSTEN
VACUUM
WELDS