Analysis of stress-strain behavior of type 316 stainless steel

Technical Report · Thu Nov 01 04:00:00 EST 1973

DOI:https://doi.org/10.2172/4388210· OSTI ID:4388210

Fahr, D.

Engineering stress-strain curves of annealed, cold-worked, and aged type 316 stainless steel were analyzed qualitatively. Atomdefect interactions were related to work-hardening rates and tensile data on the basis of serrations occurring in such stressstrain curves. Three types of serrations have been identified. The effect of varying strain rate was studied by varying crosshead speeds from 0.002 to 2 in./min in room-temperature tests and tests at 650 deg C. Only at 650 deg C had the crosshead speed a significant influence on the ultimate tensile strength and uniform plastic strain; yield strength and elongation values varied little with strain rate. The effect of test temperature ranging from 450 to 650 deg C was studied on as-annealed, annealed and aged, 20% coldworked, and cold-worked and aged specimens. Specimens aged for 4000 h were tested at their aging temperatures. Long-term aging at 450 and 550 deg C had little or no effect on mechanicalproperty data of as-annealed specimens, but affected those of previously cold-worked specimens measurably. Aging as-annealed specimens for 4000 h at 450 deg C did not lead to precipitation; at 550 deg C grain boundary precipitation took place; and at 650 deg C many precipitate particles crystallographically related to the matrix could be observed within the grains and at their boundaries. This precipitate structure led to an increased yield strength and was markedly different from that found in the recrystallized portion of cold-worked specimens aged at 650 deg C. Cold work facilitated precipitation and the formation of large sigma -phase particles. Results of the effect of short-time (10-h) aging on room-temperature tensile data, and of the influence of varying amounts of tensile prestrain on tensile data of specimens subsequently aged 4000 h and tested at 650 deg C, are also included. (auth)

• Research Organization: Oak Ridge National Lab., Tenn. (USA)
• DOE Contract Number: W-7405-ENG-26
• NSA Number: NSA-29-005471
• OSTI ID: 4388210
• Report Number(s): ORNL-TM--4292
• Country of Publication: United States
• Language: English

Related Subjects

*STAINLESS STEEL-316-- STRESS ANALYSIS
AGING
ANNEALING
ATOMS
COLD WORKING
DEFECTS
DIAGRAMS
GRAIN BOUNDARIES
HIGH TEMPERATURE
N50230* --Metals
Ceramics
& Other Materials--Metals & Alloys--Properties
Structure & Phase Studies
PRECIPITATION HARDENING
STRAIN HARDENING
STRAINS
TEMPERATURE DEPENDENCE
TENSILE PROPERTIES
TIME DEPENDENCE
VARIATIONS
YIELD STRENGTH