Silicon nitride tools for the hot rolling of high-alloyed steel and superalloy wires – Crack growth and lifetime prediction

Lengauer, Markus; Dänzer, Robert

doi:10.1016/j.jeurceramsoc.2008.02.028

Cited by 31 publications

(27 citation statements)

References 23 publications

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“…Also, the unevenness distribution of the carbide phases in the binder and the subsequent porosity thereof can be another reason of crack initiation, crack propagation and consequently a rapid fracture of the part. Since the heterogeneous distribution of the carbides in the microstructure can act as stress raisers or precursor of a brittle fracture (Ray et al, 2008;Lengauer and Danzer, 2008;Albdiry and Alethari, 2012). Similarly, Wei et al (2012) showed that the addition of higher contents of carbon to the carbides caused in crack nucleation and propagation as well as low strength of the final part.…”

Section: Characteristicsmentioning

confidence: 99%

Effect of SiC addition on mechanical and wear characteristics of WC-32(W-Ti)C-6Co cemented carbides

Albdiry

Yousif

2014

IJPTECH

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Abstract:The effect of silicon carbide (SiC) addition on mechanical and wear properties of cemented carbides was investigated in this study. Different percentages (1-7 wt. %) of SiC were added to the cemented carbides mixture of WC/ 32 wt. % (Ti-W) C/ 6 wt. % Co. The microstructural characteristics of the developed materials was identified using scanning electron microscopy (SEM) and Rockwell-A macrohardness (HRA), Vickers microhardness (Hv) as well as transverse rupture strength (TRS) were measured. The experimental results revealed that inserting SiC inclusion into the cemented carbides is found to be useless for two reasons. First, the microstructure of the developed carbides has more aggregations of largely contiguous SiC grains led to presence of rich/poor regions and consequently poor compatibility between carbides and the binder. Second, all properties of the cemented carbides greatly declined with the addition of SiC particles.

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Section: Characteristicsmentioning

confidence: 99%

Effect of SiC addition on mechanical and wear characteristics of WC-32(W-Ti)C-6Co cemented carbides

Albdiry

Yousif

2014

IJPTECH

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“…In order to tackle this problem the behaviour of a circumferential surface crack at the highest loaded position in the roll groove is analysed [12]. If -for a special traction field along the crack path (reference case) the stress intensity factor is known, it can be determined for any traction field along the crack path with the weight function method [18,19].…”

Section: Behaviour Of Surface Cracks In the Roll Groovementioning

confidence: 99%

“…3. Details of the calculation can be found in [11,12]. It is interesting to note that each of the temporal stress intensity factors own a maximum and that -depending on the time -these maxima of the stress intensity factors are positioned at different points along the crack path.…”

Section: Behaviour Of Surface Cracks In the Roll Groovementioning

confidence: 99%

“…In a consecutive paper [12] the behaviour of cracks in the roll groove of heavily loaded silicon nitride forming rollers was discussed. The analysis was based on the FE-model results described in [10,11].…”

Section: Introductionmentioning

confidence: 99%

“…In this paper the results of [12] are analysed and the time dependent behaviour of the cracks in the roll groove is described. The most important factors for the life of the tools are discussed and the processing windows for safe operations are defined.…”

Section: Introductionmentioning

confidence: 99%

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Silicon nitride materials for hot working of high strength metal wires

Dänzer

Lengauer

2010

Engineering Failure Analysis

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Abstract. For hot rolling wires, tools are nowadays made of cemented carbides. In service, these rollers suffer from wear and thermal fatigue. Due to the properties of ceramics, their use could cause improvements in tool behaviour. In field tests -when rolling materials with high deformation resistance -cracks developed in the silicon nitride rollers, which grew for a long time period before large parts of the rollers broke apart. In more moderate rolling conditions the rollers operated safely.A FE model is used to analyse the in-service behaviour of cracks in the silicon nitride rollers. For the observed crack path the stress intensity factor of the cracks is determined using the weight function method. It increases up to a crack depth of around 0.35 mm and then decreases again with increasing crack depth. This explains the observed pop-in-type growth of cracks after an overload. Depending on the rolled materials, the popped in cracks have a length of up to 1.2 mm. The further growth of the cracks to a length of several millimetres, which is caused by a fatigue growth mechanism, needs several thousand additional revolutions.

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