Effect of Boron on Liquid Zinc Induced Embrittlement in Heat Affected Zone of STKT590 Steel Tube for Power Transmission Tower

Ironmaking & Steelmaking

Suh

2015

An attempt is made, on the basis to published literature, to assess the amount of phosphorus that might be present in the steels without making it susceptible to grain boundary embrittlement. Embrittlement occurs when the general resistance to plastic flow is comparable to the stress required to separate crystals at their boundaries. A criterion is developed that enables a simple assessment to be made of the tendency to embrittle as a function of yield strength and the fraction of grain boundary sites that are covered by phosphorus. The latter is also sensitive to chemical composition, since some elements such as carbon segregate preferentially to phosphorus, giving rise to site competition that can permit a greater tolerance to the impurity. Other solutes affect the embrittling potency by different mechanisms, not all of which are clear.

Section: Trip Assisted Steelsmentioning

confidence: 99%

Is low phosphorus content in steel a product requirement?

Ironmaking & Steelmaking

Suh

2015

“…These prior boundaries become susceptible to impurity segregation and embrittlement, liquid zinc embrittlement, and any phenomenon able to exploit the disorder associated with these boundaries. [19][20][21][22] The disorder at the prior austenite grain boundaries is larger than that associated with martensite-martensite boundaries. This is because adjacent martensite plates have coherence with the parent austenite grain and hence a good fit with each other, whereas the orientation relationships between austenite grains can be random.…”

Section: Grain Boundary Embrittlementmentioning

confidence: 99%

Advances in Physical Metallurgy and Processing of Steels. Design of Ferritic Creep-resistant Steels.

2001

ISIJ International

210

Creep resistant steels must be reliable over very long periods of time in severe environments. Their microstructures have to be very stable, both in the wrought and in the welded states. This paper reviews the quantitative methods for the design of steels for elevated temperature applications. A methodology is described for the calculation of complex precipitation reactions over periods extending many tens of years. However, microstructure alone is not enough in the design of alloys. The estimation of the creep rupture stress using a neural network technique is described in the second part of this review. The calculation of the influence of solute-elements on the self-diffusivity of iron, which features in many creep equations, is an emerging area in alloy design. The methodology for such calculations is reviewed in the final section of the paper.KEY WORDS: creep strength; power plant; carbides; martensite; bainite.

“…Martensitic and bainitic steels are therefore particularly prone to temper embrittlement phenomena [7], to embrittlement by liquid zinc [8] and to failure by creep defects at the prior boundaries [9].…”

Section: C5-368 Journal De Physique IVmentioning

confidence: 99%

Martensite and Bainite in Steels : Transformation Mechanism & Mechanical Properties

1997

J. Phys. IV France

Abstract:Many essential properties of iron alloys depend on what actually happens when one allotropic form gives way to another, i.e. on the mechanism of phase change. The dependence 05 the$ mechanical properties on the atomic mechanism by which bainite and martensite grow is the focus of this paper. The discussion is illustrated in the context of some common engineering design parameters, and with a brief example of the inverse problem in which the mechanism may be a function of the mechanical properties.