Effect of structure and phase content on wear resistance of the economical alloyed metastable and secondary hardening steels of Cr-Mn-Ti system

Despite a large number of studies in the field of assessing the causes of the formation of hot and cold cracks during surfacing of wear-resistant alloys, today the issues of working out the use of economically alloyed wear-resistant materials and the technique of their surfacing remain relevant. Goal: The purpose of this work is to study the effect of the structure and phase composition on the wear resistance of economically alloyed metastable and secondary hardening steels of the Cr-Mn-Ti system, as well as with additional alloying with Mo, B, V. Mechanized surfacing was carried out with flux cored wires AN-22 and AN-20 with the supply of a de-energized additive to the head of the weld pool, which reduces the content of sulfur and phosphorus, the specific consumption of electricity and increases the assimilation of alloying elements and the relative mass of the flux. Cladding by manual arc welding was carried out with coated electrodes with the addition of a depleted CaF2-coated flux-cored wire filler. When surfacing with a de-energized additive, the ratio of the filler to the main electrode, the relative mass was determined by β = m1 / m2 (m1, m2 are the mass of the filler and the electrode rod, respectively). Submerged arc surfacing was carried out in the following modes: IN = 300 ... 350 A, UD = 26 ... 30 V, q = 6 ... 10 kJ / cm, with manual surfacing - IN = 180 ... 220 A, UD = 25 ... Results: The studies carried out confirm the possibility of the formation of a “white band” both in alloys with a high concentration of austenitizing elements (Mn, C, Ni) and when alloying carbide-forming elements with a relatively low affinity for carbon (V, Mo). The indicators of resistance to cracking (КС, j-integral, δС), and, consequently, resistance to wear of secondary hardening steels are higher than those of metastable and tool steels.

Weld Geometry, Mechanical Properties, Microstructure and Chemical Composition of AA6063 in Tungsten Inert Gas Welding with Intermittent Controlled Wire Feeding Method

In this study, AA 6063 aluminum was joined using Tungsten Inert Gas (TIG) welding with a butt joint. The ER-5356 filler metal feeding method is used intermittently to find its effect on weld geometry, mechanical properties, microstructure, and chemical composition. The dimensions of the specimens used in this study were 120 mm × 50 mm, with a thickness of 3 mm. The ratio used is the configuration of the feed time and delay time. The length ratio of wire filler is varied from a ratio of 4 to 6. The top bead width and back bead width decreased by 17.66% and 40.33%, respectively. At a ratio of 6, it has the largest cross-sectional area of 295.37 ± 27.60 mm2. The results show that the general tensile strength was proportional to the ratio, but the difference was not significant, only around ±8 MPa. The microstructure formed in each weld has different characteristics; conversely, grains with a relatively coarse structure have decreased hardness values. The chemical composition test shows that the length ratio of filler metal feed directly correlates with magnesium’s average weight content, where the weight content of magnesium value tends to be homogeneous in all areas of weld metal (WM).

Single-Pass Cladding Process Using Hot-wire Gas Metal Arc Welding Technique

The aim of this study is to improve cladding process productivity by high production rate with low dilution process by specifying technique as hot-wire GMAW process. The base metal of carbon steel A516 Gr70 was cladded by austenitic stainless steel 309LSi for creating a buttering layer and stainless steel 308LSi for hot-wire filler for topping a cladding layer in a one-pass run. The studied parameters this experiment consist of the feeding ratio of hot wire feeding speed per GMAW wire feeding speed and travel speed. Welding phenomenon during welding was observed by CCD camera with specifying the optical device to see the appropriate condition. The result showed the hot-wire GMAW cladding process could reduce cycle time 3.5 times compare with conventional FCAW cladding process. Moreover, dilution of this process could decrease lower than 15% with acceptable FN 3 on the top of weld surface. Therefore, single pass cladding process achieved by using this method with low dilution by still keep microstructure capability.

Methods of Increasing Productivity of Material Layerwise Synthesis Based on Melting Wire Filler by Electric Arc in Vacuum

Prospects of one of unconventional research areas aimed at improving additive technologies have been described. The key aspect of the proposed technology is the formation of multilayered homogeneous materials in vacuum using electric arc as a heating source, as well as using a solid metal wire as a filler metal. It is shown that this approach, compared to the available solutions applied in the global industrial production practices, will serve to increase productivity related to forming layerwise materials, as well as to resolve a number of disadvantages of the available equipment used for additive technologies implementation.

Estimating the Reliability for Asphalt Milling Machines Teeth Manufactured by Claddings Processes

The issues from the last decades related to the crisis of natural resources, raw materials, equipment, energy etc., gave rise to a new concept, namely sustainable development. The theory of sustainable development focuses on the development of quality products to provide trust and confidence, so as reliable. On this line the paper presents an approach on assessing the reliability and non-reliability of the milling teeth for asphalt machines classic manufactured and those manufactured by welding load, which give them self wear protection systems and self-lock at rotation. So in this sense there are presented comparative estimates regarding to the operating lifetime of the four batches of milling teeth for asphalt, 41Cr4 mark steel (EN 10083-1) the classic version and 3 groups of teeth load by weld on their working surface(wear) by different welding methods, namely: WIG - with filler material type tubular wire FILEUR DUR 606B, WIG – filler material with tubular type VT2, 5CrTiD rods, and MIG/MAG (CMT), the tubular wire filler material type FILEUR DUR. So, asphalt milling machines were stripped with 4 groups of teeth in order to track the behaviour during exploitation of each batch. Assuming that the product specifications properly respond customers' requirements, the level of reliability can be measured accurately by the fraction of delivered units that meet the specifications. On this line for estimating the reliability the Monte Carlo simulation method was used, which is suitable for analyzing the products that are designed to provide superior quality.

Research Regarding the Manufacture of Pipelines through Automatic Tandem MAG Welding on Generators

The manufacture of pipelines is a complex technological process starting with laminates supply, joints cutting-processing, rolling, welding, calibration, control, packing, delivery. As a rule, the technological welding process is achieved by welding on generators through MAG and submerged arc welding, procedures which generally take place completely automatically, affecting the quality and cost of products. Beside a series of advantages, submerged arc welding also has disadvantages; it does not eliminate the operator’s intervention and implies some high linear energies with implications on the mechanical-metallurgical characteristics of the welded joints. In this paper we present the preliminary results of the experiments which have been carried out on welded joints on X52 steel plate, g = 12 mm, through classical MAG welding, with one wire - filler material on the first layer, and the filling beads through tandem MAG welding, with two wires. We should mention that the plates had a V(30°) joint and the welding was executed unilaterally, horizontally, the wire - filler material being of the same quality G42 4 M G3 SI1 ( EN ISO 14341) and diameter (1.2 mm), and EN ISO 14175 protection gas. The entire technological welding process was carried out in laboratory conditions, fully robotized, using a QIROX-315 welding robot fitted with QUINTO-GLC 603-type tandem MAG welding installations, owned by ICDT-PRO-DD C12 “Advanced welding eco-technologies”, belonging to Transylvania University of Braşov.

Research of Cladded Layers Structures Changes Created by Laser Beam Technology Using a Wire Filler Material

The paper is focused on study of cladded layer properties created by laser beam, to abrasive wear resistant. As a basic material was used alloyed tool steel X37CrMoV5, the layers wascreated by laser beam by using a filler materials in the form of wire PZ 6159 and PZ 6168. The aim is research ofcladded layers structures changes, theirmicrohardness changes relative to the basic material and determine the abrasive wear resistance. One of the most important advantages of laser cladding technology is bringing the wire to the exact place of the interaction of a laser beam.

Corrosion Behavior of HAZ Between C4 Nickel-Base Alloy/X60 Steel Dissimilar Metal Weldments

C4 nickel-base alloy and X60 steel were fabricated by Tungsten Inert Gas Welding (TIG) process using a CrNiMo-3 nickel base alloy welding wire filler metal under 100A welding current. The microstructure of welding joint was analyzed by SEM. Corrosion behaviors of heat effect zone (HAZ) and X60 steel matrix were investigated by electrochemical measurement. The obtained results show that weld metal zone consists of fully dendrite structure and the austenite grain of C4 nickel-base alloy coarsening in over-heat HAZ. The HAZ of X60 steel includes coarse (GHAZ) and fine grained zones (FGHAZ). Phase change from bulk ferrite with a small amount of pearlite to granular bainite at CGHAZ. Corrosion current density of matrix of X60 steel is between FGHAZ and CGHAZ.