Creep behaviour of 12Cr-Mo-V steel weldments

Tian, Zhiling; Coussement, Carine; Witte, M.; Steen, Marc

doi:10.1016/0308-0161(91)90077-f

Cited by 7 publications

(3 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[31][32][33][34] Both a large carbide size and a low carbon content promote rapid softening of martensite during a high temperature tempering treatment. 35) The hardness profile of Fig.…”

Section: Effects Of the Pwhtmentioning

confidence: 99%

“…Effects of the PWHT Several studies of the base metal have shown that the microstructural stability of 9Cr1Mo-NbV steels, especially under high temperature ageing and creep conditions, strongly depends on the pinning of dislocations and grain boundaries by a fine distribution of carbides. [31][32][33][34] Both a large carbide size and a low carbon content promote rapid softening of martensite during a high temperature tempering treatment. …”

mentioning

confidence: 99%

See 1 more Smart Citation

High Temperature Creep Flow and Damage Properties of the Weakest Area of 9Cr1Mo-NbV Martensitic Steel Weldments

2005

View full text Add to dashboard Cite

In the present study, creep flow and damage behaviour of modified P91 steel weldments are investigated. Premature creep failure of weldments (with respect to base metal) occurs in the intercritical heat affected zone (ICHAZ). This microstructure is reproduced by thermal simulation applied to blanks cut from the base metal. Metallurgical investigations of what happens during the welding cycle show that the weakest part of the heat affected zone is heated slightly below complete austenitisation, with little (if any) carbide dissolution. During the post-weld heat treatment, extensive recovery is allowed by carbide coarsening. The intrinsic creep behaviour of the resulting microstructure is experimentally determined under controlled constraint conditions. The welding cycle strongly decreases the creep strength by increasing the creep strain rate, but not necessarily by decreasing the ductility, at least for lifetimes up to 3 500 h.KEY WORDS: 9Cr1Mo-NbV martensitic steel; intercritical heat affected zone; Gleeble 1 500 thermalmechanical simulator; High temperature creep flow and damage.in the microstructure of interest was not known, just as for cross-weld specimens. The key point of the present study is thus to determine the properties of the weakest HAZ while eliminating, as much as possible, the constraint effects due to the surrounding materials. Material and Experimental Procedures MaterialsThe study focuses on a V-shaped, circumferentially welded joint of two pipes of 295 mm in outer diameter and 55 mm in thickness. It was fabricated by submerged metal arc welding in seventeen runs followed by a post weld heat treatment (PWHT) of 2 h at 760°C. The base metal is a tempered, modified P91 martensitic steel (see Table 1 for chemical composition). Its microstructure consists of lath martensite packets with M 23 C 6 (100 nm in mean size) and MX precipitates. The filler metal has nearly the same chemical composition as the base metal (Table 1). Simulation of Welding Thermal CyclesWelding thermal cycles were applied by using a Gleeble 1 500 thermal-mechanical simulator capable of heating specimens by Joule effect at very high heating rates, corresponding to those encountered in welding conditions (i.e. 100 to 250°C · s Ϫ1). The temperature is controlled by a thermocouple spot welded onto the specimen surface. Round bars of 5 mm in diameter were used to optimise the thermal cycle and 12 mm round blanks were treated and used to machine mechanical testing specimens respectively. For each of these two geometries, the closed-loop parameters of the Gleeble 1 500 simulator were carefully adjusted in order to ensure an uncertainty lower than 2°C for the value of T peak and smaller than 1 s for the value of the cooling parameter Dt 800→500 . For specimens of 5 mm in diameter, phase transformations were continuously monitored using in-situ dilatometric measurement of the specimen diameter. To prevent from extensive oxidation of the specimen, heat treatments were performed under primary vacuum (0.1 Pa). Phase transformations moni...

show abstract

“…[31][32][33][34] Both a large carbide size and a low carbon content promote rapid softening of martensite during a high temperature tempering treatment. 35) The hardness profile of Fig.…”

Section: Effects Of the Pwhtmentioning

confidence: 99%

mentioning

confidence: 99%

High Temperature Creep Flow and Damage Properties of the Weakest Area of 9Cr1Mo-NbV Martensitic Steel Weldments

2005

View full text Add to dashboard Cite

show abstract

“…Figure 3 shows a schematic diagram of PWHT. PWHT was processed by heating time (heating rate: 220 • C/min)-holding time (4 h at 730 • C)-cooling time (furnace cooling), as shown in Figure 3 [14,15]. In the case of Alloy617 similar material welding, remarkable changes in mechanical properties were not found with PWHT [16].…”

Section: The Procedures Of Dissimilar Materials Welding and Post Weld Hmentioning

confidence: 99%

Assessing Corrosion Fatigue Characteristics of Dissimilar Material Weld between Alloy617 and 12Cr Steel Using Buttering Welding Technique

Hwang

Lee

Ahmad

et al. 2018

Metals

View full text Add to dashboard Cite

In this study, dissimilar material welding between Alloy617 and 12Cr steel was performed using the buttering welding technique on the 12Cr steel side in order to increase the weldability. After multi-pass welding, post weld heat treatment (PWHT) was performed in order to reduce the welding residual stresses, and metallurgical microstructures were observed on dissimilar material weld. Additionally, the corrosion fatigue crack growth characteristics of dissimilar material weld was assessed according to Fracture Mechanics. Based on the results, the fatigue and corrosion fatigue strength of dissimilar material weld between Alloy617 and 12Cr steel did not show a big difference prior to and after post weld heat treatment. Fatigue and corrosion fatigue crack growth of dissimilar material weld were slightly faster than those of similar material weld of Alloy617. However, the characteristics of fatigue and corrosion fatigue crack growth did not show a big difference prior to and after PWHT.

show abstract

Characterization of Tube Repair Weld in Thermal Power Plant Made of a 12%Cr Tempered Martensite Ferritic Steel

Bakić

Djukic

Rajičić

et al. 2016

Fracture at All Scales

View full text Add to dashboard Cite

Creep behaviour of 12Cr-Mo-V steel weldments

Cited by 7 publications

References 1 publication

High Temperature Creep Flow and Damage Properties of the Weakest Area of 9Cr1Mo-NbV Martensitic Steel Weldments

High Temperature Creep Flow and Damage Properties of the Weakest Area of 9Cr1Mo-NbV Martensitic Steel Weldments

Assessing Corrosion Fatigue Characteristics of Dissimilar Material Weld between Alloy617 and 12Cr Steel Using Buttering Welding Technique

Characterization of Tube Repair Weld in Thermal Power Plant Made of a 12%Cr Tempered Martensite Ferritic Steel

Contact Info

Product

Resources

About