Thick-section welding of Modified 9Cr-1Mo (P-91) steel

Technical Report · Tue Sep 01 00:00:00 EDT 1992

OSTI ID:6960775

Roberts, B W; Hackett, C D; Canonico, D A ^[1]

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1. ABB Combustion Engineering Systems, Chattanooga, TN (United States). Metallurgical and Materials Lab.

The weldability of thick sections of Modified 9Cr-lMo steel (Grade 91) has been investigated. The alloy has excellent fabricability. It is not susceptible to hot cracking on stress relief cracking. It is, as are most highly hardenable steels, susceptible to hydrogen assisted cracking but it can be avoided by good shop practice. A soft zone can occur in the heat-affected-zone which can result in Type IV cracking in service. This can be avoided through design or fabrication sequence. Strength reduction factors may also be applied. Thick sections have been successfully welded with the submerged arc, shielded metal arc and gas tunsten arc processes. The alloy because of its higher allowable stress values (2 1/2 times higher than 2 1/4CR-lMo steel at 1050{degrees}F) (566{degrees}C) permits the design of considerable thinner header sections. Further, the alloy is a viable replacement for austenitic materials at temperatures up to 1100{degrees}F (593{degrees}C) thereby eliminating or minimizing austenitic-to-ferritic dissimilar metal joints.

• Research Organization: Electric Power Research Inst., Palo Alto, CA (United States); ABB Combustion Engineering Systems, Chattanooga, TN (United States). Metallurgical and Materials Lab.
• Sponsoring Organization: EPRI; Electric Power Research Inst., Palo Alto, CA (United States)
• OSTI ID: 6960775
• Report Number(s): EPRI-TR-101394
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360101* -- Metals & Alloys-- Preparation & Fabrication
ALLOYS
ARC WELDING
CHROMIUM-MOLYBDENUM STEELS
DATA
DESIGN
ELEMENTS
FABRICATION
FATIGUE
FOSSIL-FUEL POWER PLANTS
GAS METAL-ARC WELDING
GAS TUNGSTEN-ARC WELDING
HEAT AFFECTED ZONE
HYDROGEN
INFORMATION
IRON ALLOYS
IRON BASE ALLOYS
JOINING
LIFETIME
MARTENSITIC STEELS
MATERIALS
MATERIALS TESTING
MECHANICAL PROPERTIES
METALLURGICAL EFFECTS
NONMETALS
NUMERICAL DATA
POWER PLANTS
SERVICE LIFE
SHIELDED METAL-ARC WELDING
STEAM LINES
STEELS
STRESSES
SUBMERGED ARC WELDING
SUPERHEATERS
TEMPERATURE DEPENDENCE
TENSILE PROPERTIES
TESTING
THERMAL POWER PLANTS
THERMAL STRESSES
WELDING
ZONES