Stamping a medium – sized cartridge blank from low – carbon steel

The work is devoted to obtaining a medium – sized cartridge blank from low-carbon steel. The sequence of punching transitions includes a hot back- extrusion operation, two cold draw – thinning operations, and a cold crimp operation. Modeling using the finite element method established: efforts and specific forces during operations, thermal effect during shaping, shape and size of semi – finished products with distributions of strain intensity. An elastoplastic metal model was used, which made it possible to reveal the forces of extracting the tool from deformed semifinished products and the forces of removing semifinished products from the matrix. A hollow semifinished product with the required dimensions of a protrusion on the bottom part from the side of the cavity and a protrusion on the end for forming a flange is obtained by reverse extrusion. The possibility of carrying out the first drawing operation with thinning through three sequentially located matrixes is shown. After this operation, annealing of the semi-finished product is required to restore plasticity. In the second operation of drawing with thinning and additional stamping of the bottom part, the final dimensions of this part from the side of the cavity and the shaping of the flange on the lateral surface of the semi-finished product are provided with the creation of a macrostructure to ensure the required operational properties. The shape and dimensions of the wall of the semi-finished product after the second drawing, the distribution of the intensity of deformations in it are determined from the condition of reaching the final dimensions and mechanical properties of the cartridge blank at the last crimping operation. For this, the deformations obtained as a result of the second drawing are taken into account when modeling the crimp. The proposed technology for stamping a blank of a sleeve can be implemented on a universal press – forging equipment, has a high productivity and minimizes mechanical processing.

Using 2D/3D FEM Simulation to Determine Drawing Force in Cold Drawing of Steel Tubes with Straight Internal Rifling

The most comprehensive steel tube portfolio is used to produce all kinds of modern energy production and the corresponding auxiliary unit such as boilers and heat exchangers. Multi-rifled seamless steel tubes are distinguished by maximum pressure, heat resistance, strength and durability. Production of multi-rifled seamless steel tubes by cold draw process using multi-rifled mandrel is quite a new technology. Shape and dimension of the drawing tool depend on drawing tube reduction degree, i. e. on the original diameter of the initial tube and final diameter of the tube. The technology of drawing tubes is influenced by process parameters, dimensions of tools and cold forming process conditions. Optimization of the whole forming process naturally involve the FEM analyses and simulation. One of the most important information of the cold drawing process is the load stroke of the tools. The contribution is concerned at the usability of FEM simulation on an evaluation of cold draw forming process condition and prediction of load stroke of the forming tools. DEFORM 2D/3D FEM software is used to compare the result of the drawing force and to determine the appropriate methodology to set FEM simulation of cold forming.

STRAIN INDUCED PHASE TRANSFORMATION IN Ti-15Mo β ALLOY

β-Ti alloys have been chosen for biomedical applications attributed to a combination of high strength, high fatigue resistance, good corrosion resistance and more importantly low modulus closer than other metallic materials for implants and osseointegrated prosthesis to the cortical elastic modulus (4-30 GPa). However, the phase constituents and phase transformation are still under dispute. A Ti-15Mo alloy after severe cold plastic deformation is studied to reveal the phases and phase transformation by TEM techniques. Athermal ω phase was observed in all samples evidencing the high stability of ω phase compared to β phase. However, the β to ω transformation does not proceed to a completion in heat treatment. Strain induced phase transformation happens in cold-draw wires through a coordinated shuffle of atoms along the {2 1 1}planes of β phase leading to the reduction on the <1 1 1> directions. The atomic level of shear causes the transformation of β to ω. The transformation of β to athermal ω under a train is not in a stable state but having a variable crystal structure between β and ω.

Determination of the Coefficient of Friction Under Cold Tube Drawing Using FEM Simulation and Drawing Force Measurement

The purpose of this article is to describe the methodology to define coefficient of friction between a tool and a forming material during tube cold draw technology process. In this regard, an experimental drawing process was done by using the tensile testing machine. The tensile testing machine was modified by additional equipment that allows drawing the tube. During the drawing, the force was recorded. Subsequently, the finite element simulation of cold draw forming was used to generate load-stroke curves with different friction coefficient. The friction coefficient was estimated by comparing the load stroke and the force recorded curves.

Why Surface Treatment is must for Cold Drawing Mild Steel Tubes

Cold Draw Welded (CDW) tubes find a wide array of applications in the automobile industry. Electric Resistance Welded (ERW) tubes are surface treated with certain chemicals to make them eligible for cold drawing. The surface treatment is a time consuming process. Efforts have been directed to eliminate it altogether or at least to reduce its cycle time. We have assiduously conducted certain trials to establish the nature and character of the surface treatment. With the knowledge thus generated, we have, in our capacity, attempted to analyze why surface treatment is sine qua non to cold draw.

Study on Anti-Stress Relaxation Behavior of Non-Quenched Steel

The cold draw MFT8 steels with different reduction in cross sectional areas were investigated to understand the effect of aging time on the anti-stress relaxation ability of non-quenched and tempered steel. The hardness and the anti-stress relaxation ability of cold draw NQT MFT8 steel was improved after aging at 300°Csince the precipitation of submicron particles within deformed ferrite. The cold draw NQT MFT8 becomes harder and more resistant to stress relaxation with increasing aging time. The cold draw MFT8 with both 25% and 30% reduction in cross sectional areas are stress relaxation resistant after aged at 300°C for 2 hours.

Design of Combined Helical Blade Manufacturing Device

A new machine is presented in this paper, which is designed to cold draw helical blade. The new machine has characteristics as conserving time and labor, simple to manufacture, strong adaptability and no energy required. It is suitable especially for making helical blades in small amount when repairing helical conveyor. The principle of work and structure of the helical blade manufacturing device is presented, the calculation of cold draw helical expanded blade is also provided.

Fatigue Behavior and Microstructure of Pt-20Ir Wire as Lead Conductor in Implantable Medical Device

Pt-20Ir cold draw wire has been used as lead conductor in implantable medical devices. The lead is a medical device to transfer the electrical signal from a implanted stimulator to the body area for stimulating such as brain and neurological nerves. In this study, fatigue behavior and failure mechanism of Pt-20Ir wire was studied with rotary bending fatigue testing. The relations between the cyclic strain amplitude (ε) and the cycles to failure (N) were obtained and compared with MP35N wire which is the most commonly used metal wire as lead conductors. The results show Pt-20Ir cold drawn wire (0.102 mm) has a fatigue endurance strain limit of 0.18% which is significant lower than that of MP35N wire. Microstructure of Pt-20Ir cold draw wire was also analyzed. Results show that the grain size of in wire is elongated like bundled fiber structure. The texture of wire is strongly fiber textured and with a strong gradient from outside layer to center of the wire. Near surface region has <111> textured grain and around center region of the wire has <100> textured grain. The center of grain also has larger size than near surface.

Three-Phase Characterization of Uniaxially Stretched Linear Low-Density Polyethylene

This study comprises a detailed morphological study of cold-drawn polyethylene monofilaments by Raman spectroscopy, differential scanning calorimetry (DSC) and X-ray measurements. The structure of the three-phase morphology of the linear low-density polyethylene monofilaments was investigated by combining these measurements. It was found that the most important structure variation was found in the intermediate or rigid amorphous phase, whereby the amounts of crystalline and amorphous phases were nearly constant and almost independent of the cold-draw ratio. The intermediate third phase contains gauche and transmolecules, and the amount of transmolecules was increased with the cold-draw ratio and was directly related to this cold-draw ratio. It was found that the two peaks in the Raman spectra, respectively, at 1303 and 1295 cm-1, can be correlated to the amount of gauche and transmolecules in the polyethylene monofilaments. A good and new insight into the three-phase morphology was obtained by combining the DSC and X-ray measurements with the amounts of trans- and gauche molecules from the Raman spectra analysis.