Search results

During steel design, the best technique to achieve optimal properties has been used, wiz. steel microalloying with nitrogen accompanied by some alloying elements like V and Al [1, 2].
Chemical composition of the steel 17Mn2NV Weight fraction of the elements [%] C Mn Si S P V N Al Ca 0.18 1.36 0.55 0.008 0.006 0.08 0.024 0.014 0.02 Contents of residual elements, %: As - 0.006; Sn - 0.0067; Zn - 0.0043; Pb - 0.0001.
A reduction of the difference between TS and YS is characteristic; it decreases to 50 N/mm² at 700°C (Fig. 4). 0 100 200 300 400 500 600 700 800 0 200 400 600 800 Testing temperature, oC TS, YS, N/mm2 0 50 100 150 200 250 El., R. of A., % KCU, J/cm2 TS YS Elongation Reduction of Area KCU Figure 4.
Table 3 - Results of bending, ageing and unbending test on the reinforcing steel bars Mechanical properties range Bar diameter, mm YS, N/mm² TS, N/mm² El., % Cold bending by 90° Bending by 20° after ageing 14 (5 bars) 570-590 720-750 18-20 valid* valid * *Note: "valid" means that sample after bending in the aged condition exhibited a sound surface, i.e.
The levels of tensile properties and fatigue characteristics obtained were: YS ≥ 500 N/mm², TS ≥ 700 N/mm², El. ≥ 20%, Agt ≥ 10.3, σ-1smooth = 412 N/mm², σ-1notched = 250 N/mm² on a base of 107 cycles.

The microstructure of the as-cast alloy consists of α-Mg, Mg2Sn and Mg32(Al,Zn)49 phases.
Area C riched in Mg, Zn and Al is confirmed as the Mg32(Al,Zn)49 phase.
Liao, Effects of Sn addition on microstructure and mechanical properties of Mg-Zn-Al alloys, J.
Kim, Development of creep resistant die cast Mg-Sn-Al-Si alloy, Mater.
Park, Microstructural characterization and mechanical properties of Mg-xSn-Al-Zn alloys, Arch.

Scot et al presented a formulation and solution for the multi-objective optimization problem for the selection of the best control settings parameters for the wire electric discharge machining process.
REFERENCES [1] Hewidy.M.S, El-Taweel, T.A, El-Safty.M.F 'Modeling the machining parameters of wire electric discharge machining of inconel 601 using rsm', Journal of material processing technology Vol. 169, (2005) pp. 328-336

After the heat treatment, testing of mechanical properties was carried out focused on YS and TS, elongation (El.), CVN and Brinell hardness (HBW) testing.
Table 2 Cylinder’s mechanical properties after 4 applied modes of the HT HT mode YS [MPa] TS [MPa] El. [%] CVN longitudinal [J.cm-2] CVN transverse [J.cm-2] HBW (2,5/187,5) [-] HT1 973 1064 16.5 118 69 336 HT2 1175 1241 13.2 39 29 387 HT3 1223 1300 14 35 34 396 HT4 1091 1179 13.2 36 31 368 After the testing of mechanical properties, the metallographic observation focused on evaluation of obtained microstructures, grainsize and micropurity was realized.
Similar results were also presented by Oliveira et al. [5].

The load separation method is based on the work of Paris et al. [5].
Fig. 2 Moment versus half rotation angle curve for the pipe fracture test Fig. 1 Load versus load-line displacement curves for J-R test of various 1/2TCT specimens W v v W b G P P pl N N =       = (2) Where, 0PCv vvv el el pl = −= C0: initial elastic compliance of specimen For calculating the plastic part of load-line displacement, the elastic displacement calculated from elastic compliance of CT specimen is removed and the plastic displacement is normalized by specimen width, W.

El-sayed Abdo, M.
A, El-Guebaly, “ARIES-ST nuclear analysis and shield design”, Fusion Engineering and Design, vol. 65 (2003), pp. 263-284
Dubois, Cabuil V, et al, “Monodisperse magnetic nanoparticles: Preparation and dispersion in water and oils”, J Mater Res, vol. 13 (1998), p. 2975

Elemental analysis was performed by a Vario EL III analyzer.
Al-Abdullah, I.A.
El-Emam: Eur.

There are several approaches by Chajes et al. [1], Bizindavyi et al. [2], Chen & Teng [3], El-Mihilmy et al
[4], Nakaba et al. [5], Kim et al. [6] and Oller [7].
[4] El-Mihilmy, M., Tedesco, J. (2001).

The work of Philips et al. [11] was improved upon by Chekuri et al. [9] to yield total completion time upper bound that is 1.58 times the optimal value of total completion time.
Using the notations of Graham et al. [16], the problem is represented as 1 | ri |∑= n i iC 1 .
[6] E.L.
Graves et al., editor, Handbook in Operations research and management science, Vol. 4 (1993) , pp. 445-522
Graham, E.L.

References [1] Tlaq J H, El-Hawary F, El-Hawary M E.
[3] Bahmani-Firouzi B, Farjah E, et al.
[4] Aghaei J, Niknam T, et al.
[11]Rajkumar M, Mahadevan K, et al.
[13] Weiqing Zhou, Zongliang Qiao,Fengqi Si,et al.