Search results

Furthermore, these manufacturing processes always result in poor part properties, such as the reduced material strength.
Parameters Values Material mark AISI 1035 steel Young’s modulus 2×105 MPa Possion ratio 0.3 Material properties C = 700 MPa, N = 0.15 Finite element model.
The unevenness of the compressive stress directly affects the degree of bending of the blank, and the pit finally forms.
China Mechanical Engineering., 27(2016) 3098-3102
Journal of Mechanical Science and Technology. 30(2016) 2723-2729.

To achieve the flaw acceptance criteria of girth welds by ECA, a variety of mechanical property tests are performed, such as tensile test, Charpy impact test, fracture toughness test and etc.
A girth weld is located in the mid-length of the specimen, while an artificial machined notch or fatigue sharpened flaw is introduced in the weld centerline or heat- affected zone.
Table 1 shows the mechanical property of the pipe and the weld.
Table1 Material property of the X80 grade pipe and the fabricated girth weld.
(2) (3) (4) (5) Where, is the stress-intensity factor, E is Young’s modulus, ν is Poisson’s ratio, is the depth of the flaw, is the half of the flaw length, and is the pipe thickness.

While selective sulphidation to form a barrier layer sulphide will be governed by the free energy of formation, the kinetics of this selective process and hence the overall rate of sulphidation will be controlled by the defect structure of the sulphides (Table 3), their ability to support fast or slow diffusion rates as measured by self-diffusion coefficients (Table 4) and melting points and mechanical stability indicated by the Pilling-Bedworth ratio.
These properties indicate that the refractory and reactive metal nitrides are highly stable compounds and can be used in coating forms to provide barriers against diffusion and high temperature environmental degradation.
Other factors that need consideration are the mechanical stability of the sulphides (BS) as assessed by the PillingBedworth ratio and the transition between external and internal sulphidation influenced by species permeability, solute diffusivity and other thermodynamic factors determined by the volume fraction of the sulphides present.
Table 3 Physico-chemical properties of sulphides of certain Group III-VI metals Sulphide Pilling-Bedworth ratio Defect structure Melting point (o C) Al2S3 2.60 n-type 1099 TiS2 1.11 n-type 1999-2099 ZrS 1.91 n-type 1549 HfS - - 2100-2273 (est) V2S3 - n-type 1799-1999 NbS2 - n-type - TaS2 2.42 n-type 999 Cr2S3 2.50 (CrS) n/p-type 1550 (CrS) MoS2 3.54 n-type 1457 WS2 3.47 n-type >1800 FeS 2.50 p-type 1189 Co9S8 2.37 p-type 1080 NiS 2.50 p-type 796 Table 4 Self-diffusion coefficients of cations (DM) in some metal sulphides and oxides Sulphide Temperature (o C) DM (cm 2 /s) Oxide Temperature ( o C) DM (cm 2 /s) Cu2+yS 650 5.15 x 10 -5 Cu2-yO 1000 1.7 x 10 -8 Co1-yS 720 7.0 x 10 -7 Co1-yO 1000 1.9 x 10 -9 Ni1-yS 800 1.4 x 10 -8 Ni1-yO 1000 1.0 x 10 -11 Fe1-yS 800 3.5 x 10 -7 Fe1-yO 800 1.3 x 10 -8 Cr2S3 1000 1.0 x 10 -7 Cr2O3 1000 1.0 x 10 -12 Al2S3 600 1.0 x 10 -13 Al2O3 1000 1.0 x 10 -16 Consideration of
It should be pointed out that such localised attack did not affect the overall integrity of the coatings.

Therefore, it is necessary both the selection of suitable parameters in the welding, that maintain a balance between the properties of mechanical resistance and tenacity, as well as obtaining indications as to the susceptibility to embrittlement by hydrogen, reducing the risk of the occurrence of this phenomenon in the materials for transport of Oil and Gas.
Traction tests were performed on each welded EPS and MB, adopting a constant displacement velocity of 0.5 mm/min, to identify fracture morphology. and the mechanical properties are shown in Table 5.
The properties indicate a small decrease in the elongation of the specimen in relation to EPS 1 and an increase in the flow limit, compared to EPS 2 and MB, with fractures occurring in the region of the base metal.
Table 5 – Mechanical properties obtained in the tensile tests according to EPS 1, 2 and MB.
This increased resistance in EPS 1 can be considered a susceptibility factor to hydrogen embrittlement.

The main benefits are improved mechanical properties at reduced weight in comparison with conventional metal parts.
In addition, automated manufacturing processes such as resin transfer moulding or injection moulding are being increasingly used to manufacture complex three-dimensional parts in high unit numbers. [1] The mechanical properties of FRPs are greatly affected by the local fibre orientation or the weaving or breading architecture, the yarn spacing or the local fibre packing density [2].
For materials characterisation there are only a few non-destructive techniques available to analyse these properties.
Using the directional properties of the SDFI, different fibre orientations in the CFRP sample are imaged independently.
[2] Neumeister J., Jansson S., Leckie F, The effect of fiber architecture on the mechanical properties of carbon/carbon fiber composites, Acta Materialia. 44 (1996) 573–585

Abstract: In this study, we investigate the characteristics of activated sludge pretreated with microwave irradiation and the factors influencing the microwave effects.
The microwave output power was one of the most important factors for improving the dewatering of activated sludge when all other parameters of activated sludge and microwave frequency were held constant.
However, reducing sludge’ water percent content below 80% when the activated sludge has been conditioned by commonly used conditioners is more difficult than by mechanical means [8].
However, longer exposure times than 40s adversely affect the sludge settling ability as shown in Figure 2.
(4) Lastly, the power of the microwave source is the most important factor when the microwave frequency and the properties of sludge are held constant.

Previous researcher has suggested that the hypersensitive lines are strongly affected by changes in the symmetry of the field on the lanthanide ion [19-20].
Gowda, Effect of Bi3+ Ions on Physical, Spectroscopic and Optical Properties of Nd3+ Doped Sodium Diborate Glasses, Physica B 426 (2013) 58-64
Unnikrishnan, Spectroscopic Properties of Er3+ ions in multicomponent Tellurite Glasses, Journal of Luminescence 159 (2015) 55-65
Huy, Judd-Ofelt Analysis of Spectroscopic Properties of Sm3+ions in K2YF5 Crystal, Journal of Alloys and Compounds 520 (2012) 262-265
Awang, Structural and Optical Properties of Erbium Doped Zinc Sodium Tellurite Glass: Effects of Gold Nanoparticles, (2014) PhD Thesis UTM

Introduction The residual stress distributions in components are not uniform because they have heating and mechanical histories.
In the case of a weld, a high residual stress is induced by the heat history at the joint, and this is one factor causing fatigue and stress corrosion cracking.
This is important in order to ensure the reliability of the products, since reliability is affected by changes in the crack extension properties.
One of the factors of this difference is the residual stress distribution within the gage volume.

Pumice was selected as the catalyst in the present study due to its excellent chemical and configurable properties, such as high mechanical strength and chemical stability. pCNB, as a special indicator of ·OH, is chosen as the target organic compound due to its refractory nature to conventional chemical oxidation.
As Figure 4 indicated, temperature was a vital factor for the degradation efficiency of pCNB in the pumice-catalyzed ozonation processes.
The stability and reusability of the catalyst are important factors in catalyzed reactions for practical industrial applications, the stability of the pumice catalyst was investigated by reuse of one sample of catalyst in five successive ozonation experiments.
It was not known whether the catalytic ozonation process could affect the characteristics of pumice catalysts or not.

This water provides to the raw material some ductile properties and thus allows it to be formed and to keep the geometry.
The understanding of the scientific links between the moisture, the rheological properties of the clay paste, and the final product (structure, aspect, mechanical properties) is fundamental to guarantee a high yield of the manufacturing process.
During the firing step, the sand forms a network, which allows to give the final mechanical properties.
Experimental setup To identify the rheological behaviour of the clay paste, we performed compression tests using an electro-mechanical testing machine, equipped with a 30 kN load cell.
The moisture affects the formability of the tile.