Study on Production Process, Microstructure, Properties of 15MnNbR Pressure Vessel Steel

2022 ◽  
Vol 905 ◽  
pp. 78-82
Author(s):  
Lu Lu Feng ◽  
Wei Wen Qiao ◽  
Zeng Qiang Song ◽  
Zhi Mei Cao ◽  
Yan Jun Yang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Production Process ◽  
Pressure Vessel ◽  
Controlled Rolling ◽  
Pressure Vessel Steel ◽  
Vessel Steel ◽  
Toughness Testing ◽  
Low Temperature Impact Toughness ◽  
Strength And Toughness

The production process, microstructure, and mechanical properties of 15MnNbR pressure vessel steel were studied by optical microscopy, universal tensile testing, and low-temperature impact toughness testing. It was found that the microstructure obtained after controlled rolling and cooling (known as thermo-mechanical control processing) consisted of ferrite and pearlite with non-uniform grain size. The banded microstructure was prominent, the strength was high, and the toughness was poor. After normalizing, the grain size was refined, both the microstructural uniformity and the banded microstructure were improved, and the strength and toughness of the steel were enhanced. After normalizing and water cooling, the grain was further refined, the microstructure was homogenized, the banded microstructure disappeared, and the strength and toughness of the test steel were improved simultaneously, resulting in excellent comprehensive mechanical properties.

The Consequences of Macroscopic Segregation on the Transformation Behavior of a Pressure-Vessel Steel

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
E. J. Pickering ◽  
H. K. D. H. Bhadeshia
Keyword(s):  
Mechanical Properties ◽  
Pressure Vessel ◽  
Large Scale ◽  
Pressure Vessels ◽  
Pressure Vessel Steel ◽  
Vessel Steel ◽  
Chemical Segregation ◽  
Compositional Variations ◽  
Grade 3 ◽  
Kinetics Of

It is important that the material used to produce high-integrity pressure vessels has homogeneous properties which are reproducible and within specification. Most heavy pressure vessels comprise large forgings derived from ingots, and are consequently affected by the chemical segregation that occurs during ingot casting. Of particular concern are the compositional variations that arise from macrosegregation, such as the channels of enriched material commonly referred to as A-segregates. By causing corresponding variations in microstructure, the segregation may be detrimental to mechanical properties. It also cannot be removed by any practically feasible heat treatments because of the large scale on which it forms. Here we describe an investigation on the consequences of macrosegregation on the development of microstructure in a pressure-vessel steel, SA508 Grade 3. It is demonstrated that the kinetics of transformation are sensitive to the segregation, resulting in a dramatic spatial variations in microstructure. It is likely therefore that some of the scatter in mechanical properties as observed for such pressure vessels can be attributed to macroscopic casting-induced chemical segregation.

scholarly journals Investigation of the Effects of Submerged Arc Welding Process Parameters on the Mechanical Properties of Pressure Vessel Steel ASTM A283 Grade A

2017 ◽  
Vol 2017 ◽  
pp. 1-8
Author(s):  
Prachya Peasura
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Process Parameters ◽  
Pressure Vessel ◽  
Arc Welding ◽  
Travel Speed ◽  
Submerged Arc Welding ◽  
Pressure Vessel Steel ◽  
Vessel Steel ◽  
Submerged Arc

The pressure vessel steel is used in boilers and pressure vessel structure applications. This research studied the effects of submerged arc welding (SAW) process parameters on the mechanical properties of this steel. The weld sample originated from ASTM A283 grade A sheet of 6.00-millimeter thickness. The welding sample was treated using SAW with the variation of three process factors. For the first factor, welding currents of 260, 270, and 280 amperes were investigated. The second factor assessed the travel speed, which was tested at both 10 and 11 millimeters/second. The third factor examined the voltage parameter, which was varied between 28 and 33 volts. Each welding condition was conducted randomly, and each condition was tested a total of three times, using full factorial design. The resulting materials were examined using tensile strength and hardness tests and were observed with optical microscopy (OM) and scanning electron microscopy (SEM). The results showed that the welding current, voltage, and travel speed significantly affected the tensile strength and hardness (P value < 0.05). The optimum SAW parameters were 270 amperes, 33 volts, and 10 millimeters/second travel speed. High density and fine pearlite were discovered and resulted in increased material tensile strength and hardness.

A Micromechanics Approach for Assessing the Applicability of Precracked Charpy Specimens to Determine the T0 Reference Temperature

2013 ◽  
Author(s):  
Rafael G. Savioli ◽  
Claudio Ruggieri
Keyword(s):  
Fracture Toughness ◽  
Cleavage Fracture ◽  
Pressure Vessel ◽  
Reference Temperature ◽  
Pressure Vessel Steel ◽  
Vessel Steel ◽  
Toughness Testing ◽  
The Relationship ◽  
Resistance Data ◽  
Weibull Stress

This work describes an application of a micromechanics model for cleavage fracture to determine the reference temperature for pressure vessel steels from precracked Charpy (PCVN) specimens. A central objective is evaluate the effectiveness of the Weibull stress (σw) model to correct effects of constraint loss in PCVN specimens which serve to determine the indexing temperature T0 based on the Master Curve methodology. Fracture toughness testing conducted on an A285 Grade C pressure vessel steel provides the cleavage fracture resistance data needed to estimate T0. Very detailed non-linear finite element analyses for 3-D models of plane-sided SE(B) and PCVN specimens provide the evolution of near-tip stress field with increased macroscopic load (in terms of the J-integral) to define the relationship between σw and J from which the variation of fracture toughness across different crack configurations is predicted. For the tested material, the Weibull stress methodology yields estimates for the reference temperature, T0, from small fracture specimens which are in good agreement with the corresponding estimates derived from testing of much larger crack configurations.

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