Advanced Materials Research Vols. 291-294

Abstract: The joint property of aldary (T3 copper, B5 cupronickel and H96 brassiness) with 35CrMnSi by the use of inertial radial friction welding techniques is studied to meet the requirements of product operation . The microstructure of the welding joint, shear testing, vickers hardness and electron probe tests are carried out to verify the material weldability. The results show good performance of T3 copper, B5 cupronickel and H96 brassiness welded well with steel. The joints shear strength is more than 200Mpa, and no air hole flaw in weld seam that often occur in general fusion welding with dissimilar material. The welding properties can satisfy the requirements of the products. The results also indicate that under the same welding specification, the region of HAZ is related to thermal conductivity and melting point of copper-alloy, the microstructures of HAZ on B₅＋35CrMnSi steel side is wider than others .

Abstract: Tube and shell condenser is an important component of soybean softening equipment, and its structure is Q235B welding with 304 austenitic stainless steel pipes. During the using process of this product, it appears crack failure .In order to find the reason of crack failure, the welded joint was analyzed by SED, XRD, EDXRF and metallographic microscope in detail, and some improvement measures and solutions are put forward to avoid crack failure in this paper.

Abstract: The effect of welding heat input ranging from 1.507 KJ/mm to 2.987KJ/mm on low temperature toughness of deposited metal made by self-shielded flux-cored wire has been investigated. The results showed that low temperature toughness decreased with the increase of heat input, and the impact fracture changed from ductile to cleavage fracture. In addition, the chemical compositions demonstrated a slight tendency to decrease with increasing heat input. While, heat input has little effect on inclusions of deposited metal. Higher heat input lead to grains coarsened further, reduced acicular ferrite and granular bainite, and increased polygonal ferrite, which mainly lead to toughness decreased.

Abstract: ‘Tanggam’ system is a main method of joining woods which is applied in Malay traditional building. it works by connecting two small components of a building and yet combining it to form the main structure of the building. there are only small numbers of writing that discuss in tanggam available in malaysia and most of the discussion are focusing on methods of producing tanggam, the types and application of tanggam in construction. In order to conserve this great heritage, the area of study need to be widens to others scopes. This is the way to maintain the use of tanggam in future. Generally, the ‘sistem tanggam’ varies in design, functions and strength where the strength of the tanggam is mainly depends on the tanggam connection design. In this study, a typology framework is created based on the previous writing on tanggam system. This typology will try to connect the design, the strength and also the area of application of the tanggam in Malay building.

Abstract: High energy pulse precision cold–welding technology is a new welding technology that using high-energy pulsed, which arc produced between tungsten electrode and the workpiece, to melt the base metal and welding wires quickly. The quality and accuracy of this technology are equal to laser welding. It can repair the surface of parts, pitting, cracks and other defects of special-shaped surface. This article discusses research process of the High energy pulse precision cold–welding technology and its working principle, performance characteristics and equipments. It also presents the technology of cold welding materials and processes to explore the High energy pulse precision cold–welding technology’s potential application and future development in the field of surface engineering.

Abstract: The welding seam identifying(WSI) is one of remote welding precondition. The welding seam is usually identified by vision sensor. The investigation on WSI based on force sensing is less reported. Because the interaction mechanism of friction is not clear in 6 dimension(6D) force of WSI, the influence of friction on the WSI feed and direction is studied. The experimental results show that the friction will decrease the WSI feed in XSY plane and increase in Z direction, but they is in range permitted by WSI. The friction makes WSI feed direction point to the middle of welding seam track, and do not influence WSI. Above technologies, The WSI of S groove is achieved. The average deviation of WSI is less than ±0.5mm when there is friction in 6D force of WSI. It can meet the precision of WSI in remote welding.

Abstract: 21% Cr with Ti-Nb dual stabilized ferritic stainless was welded using Nd: YAG laser. The relationship between microstructure and parameters of laser welding was examined. The microstructure was investigated by using the optical microscope and scanning electron microscopes. The average grain size of the HAZ was increased with increasing heat input due to the slow cooling rate. Large precipitates as TiN, TiC and Nb(C,N) were dissolved in the HAZ. Fine precipitates which supposed to be TiC was formed uniformly distributed in the case of the fusion zones.

Abstract: The diffusion welding between aluminum alloy and steel was achieved in this study. The influence of welding temperature on the interfacial microstructure and tensile shear strength of the joint were investigated. The joint with 101.3 MPa was obtained under the condition of the welding temperature of 525 °C. The results reveal that the reaction layer thickness increases with the increasing of welding temperatures and that the reaction layer consists of Al₅Fe₂ and Al₁₃Fe₄ formed in the interface. The strength of the joint is related to the reaction layer thickness and when the reaction layer thickness was approximately 0.8 μm, the value of the joint strength reached maximum.

Abstract: The tensile mechanical properties of bamboo mat and curtain plywood（for short bamboo plywood）were studied through “electrometric method”. It was proved that in the range of elastic deformation，the Poisson′s ratio and the elastic modulus of the bamboo plywood were not constant. The Poisson′s ratio of the bamboo plywood decreased nonlinearly with the load increase that Poisson′s ratio decreased markedly when the load was less than 1kN，and decreased gently when more than 1kN.The tensile elastic modulus of the bamboo plywood also increased nonlinearly with the load increase that the tensile modulus of elasticity increased drastically when the load was less than 800N，and increased less when exceeded 800N. In the process of loading，the tensile deformation、the tensile stress and strain all increased linearly with the load increase，and the tensile stress and strain both were linearly relevant to tensile deformation.

Abstract: Based on the superiority avoiding the matrix equation to be morbid for those fitting functions constructed by orthogonal base, the Legendre orthogonal polynomial is adopted to fit the experimental data of concrete uniaxial compression stress-strain curves under the frame of least-square. With the help of FORTRAN programming, 3 series of experimental data is fitted. And the fitting effect is very satisfactory when the item number of orthogonal base is not less than 5. What’s more, compared with those piecewise fitting functions, the Legendre orthogonal polynomial fitting function obtained can be introduced into the nonlinear harden-soften character of concrete constitute law more convenient because of its uniform function form and continuous derived feature. And the fitting idea by orthogonal base function will provide a widely road for studying the constitute law of concrete material.