Effect of strength and structure on resistance to brittle fracture of low-alloy steels

1975 ◽  
Vol 7 (2) ◽  
pp. 207-209
Author(s):  
A. V. Velikanov ◽  
A. P. Babich
Keyword(s):  
Brittle Fracture ◽  
Low Alloy Steels ◽  
Alloy Steels ◽  
Resistance To Brittle Fracture

On the definition of the local brittle fracture criterion to predict the crack resistance of high-strength steel

2020 ◽  
pp. 114-134
Author(s):  
A. V. Ilyin ◽  
A. A. Lavrentiev ◽  
A. V. Mizetsky
Keyword(s):  
Brittle Fracture ◽  
Crack Resistance ◽  
Large Angle ◽  
Energy Condition ◽  
High Strength ◽  
Low Alloy Steels ◽  
Structural Barriers ◽  
Steel Sheets ◽  
Alloy Steels ◽  
Definition Of

The use of local brittle fracture criteria for predicting the crack resistance of low-alloy steels is a generally accepted approach. The paper analyzes the possibility of its use for experimental melts of highstrength low-alloy steel sheets with yield strength of about 1000 MPa, the structural state of which was previously studied. Cylindrical specimens with an annular notch of three types differing in the stress-strain state in the net cross-section were tested. It is found that the use of the simplest formulation of such a criterion in the form of an energy condition for the propagation of microcracks through structural barriers (large-angle grain boundaries) gives acceptable results for notched specimens made of metal with different grain sizes, and allows linking these results with the crack resistance of the studied materials.

A Case Study in Temper Embrittlement of Fluidized Catalytic Cracking Components

2014 ◽  
Author(s):  
Matthew Bowen ◽  
William F. Newell ◽  
Jorge Penso
Keyword(s):  
Brittle Fracture ◽  
Catalytic Cracking ◽  
Temper Embrittlement ◽  
Charpy Impact ◽  
Impact Testing ◽  
Low Alloy Steels ◽  
Microstructure Observation ◽  
Fluidized Catalytic Cracking ◽  
Alloy Steels

As described in API RP 571, temper embrittlement is the reduction in toughness due to a metallurgical change that can occur in some low alloy steels as a result of long term exposure in the temperature range of about 650°F to 1070°F (343°C to 577°C). The loss of toughness is not evident at operating temperatures; however, equipment that is temper embrittled may be susceptible to brittle fracture during start-up and shutdown. 2.25 Chromium 1 Molybdenum steel used in the petrochemical industry is known to be susceptible to temper embrittlement. Most guidance to prevent temper embrittlement is oriented to heavy wall hydroprocessing reactors. In this work, a case history is presented where Fluidized Catalytic Cracking (FCC) components less than one inch in thickness exposed to temperatures in the 900°F to 1000°F (482°C to 538°C) range experienced temper embrittlement. Metallurgical analysis that included chemical analysis, microstructure observation, and charpy impact testing at different temperatures before and after heat treatment helped to identify the embrittlement cause. Several considerations to mitigate the risk in the short term including inspection, definition of minimum metal temperature to prevent brittle fracture, fitness for service, and modification of operational procedures, as well as long term considerations, including pipe component replacement, are described. Additional work regarding the selection of filler metals, welding procedure qualification tests that include step cooling tests, and learning that included bead sequence and heat input controls are also described. Applicable API RP 934-A [Ref. 6] recommendations were incorporated into the project specification for this work, such as the consideration of chemical restrictions for this alloy, not only for heavy wall applications but also for thinner wall applications working in the temper embrittlement range.

Susceptibility to brittle fracture of low-alloy steels with additions of niobium, vanadium, and nitrogen

1974 ◽  
Vol 16 (1) ◽  
pp. 35-37
Author(s):  
M. V. Pridantsev ◽  
F. I. Kochin ◽  
S. G. Fetisov ◽  
N. T. Pavlenko
Keyword(s):  
Brittle Fracture ◽  
Low Alloy Steels ◽  
Alloy Steels

Effects of cooling rate on the mechanical properties of dual phase treated vanadium steels

1983 ◽  
Vol 41 ◽  
pp. 220-221
Author(s):  
L.J. Chen ◽  
H.C. Cheng ◽  
J.R. Gong ◽  
J.G. Yang
Keyword(s):  
Mechanical Properties ◽  
Cooling Rate ◽  
Automobile Industry ◽  
High Strength ◽  
Weight Percent ◽  
Low Alloy Steels ◽  
Dual Phase ◽  
Resource Requirement ◽  
Alloy Steels ◽  
Potential Weight

For fuel savings as well as energy and resource requirement, high strength low alloy steels (HSLA) are of particular interest to automobile industry because of the potential weight reduction which can be achieved by using thinner section of these steels to carry the same load and thus to improve the fuel mileage. Dual phase treatment has been utilized to obtain superior strength and ductility combinations compared to the HSLA of identical composition. Recently, cooling rate following heat treatment was found to be important to the tensile properties of the dual phase steels. In this paper, we report the results of the investigation of cooling rate on the microstructures and mechanical properties of several vanadium HSLA steels.The steels with composition (in weight percent) listed below were supplied by China Steel Corporation: 1. low V steel (0.11C, 0.65Si, 1.63Mn, 0.015P, 0.008S, 0.084Aℓ, 0.004V), 2. 0.059V steel (0.13C, 0.62S1, 1.59Mn, 0.012P, 0.008S, 0.065Aℓ, 0.059V), 3. 0.10V steel (0.11C, 0.58Si, 1.58Mn, 0.017P, 0.008S, 0.068Aℓ, 0.10V).

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