Structure and Tribological Properties of Chromium Coatings Formed by Electrodeformation Cladding with Flexible Tools

The paper contains results of investigations on structure and tribotechnical properties of chromium coatings formed by a method of electrodeformation cladding with flexible tools (EDCFT). The purpose of these investigations is to assess prospects for application of the coatings as an alternative to galvanic chrome plating which is widely used in manufacturing hydraulic cylinder rods of metal-cutting machines. Rotary metal brushes with a wire pile made of 65Г-steel and 03Х17Н14М2-stainless steel have been used as a flexible tool. A compacted bar obtained by sintering a mixture of pure chromium powders and a nano-sized diamond-graphite blend UDDG has been employed as a donor material for EDCFT. According to results of the research it has been established that alloying elements of wire pile such as chromium and nickel are added to a coating composition while forming coatings a stainless steel brush. So in the case of using brushes with wire pile of 03X17H14M2-stainless steel the amount of chromium and nickel in a clad coating layer is 5.3 and 9.6 times higher in percentage, respectively, in comparison with the coating formed by a 65Г-steel brush that can contribute to improvement of coating corrosion resistance. At the same time, surface relief of the coating has a developed rough structure consisting of chromium microparticles having various size that are tightly packed and elongated in the direction of brush rotation and there are no flaws in the form of discontinuities and delaminations. Tribological tests have been performed under conditions of “boundary lubrication” on a rotary friction machine that implements friction of a rubber indenter on a flat surface of a rotating disk. According to data of the tribotechnical tests it has been ascertained that under conditions of “boundary friction” for such paired samples as “coated disc – rubber roller” chromium coatings formed by the EDCFT method, have the lowest values of a sliding friction coefficient (fтр = 0.023) which are 7.5 times lower than chromium coatings obtained by electroplating. At the same time the wear of rubber rollers in pairs with electroplated chromium coatings has turned out to be less than in pairs with the coating formed by the EDCFT method.

Theoretic and Experimental Research of Crankshafts Barrel Finishing

At present, crankshafts with larger size are finished mostly by abrasive cloth and manual steel brush, which is not ideal on finishing quality, efficiency and cost, especially cleanness degree does not meet design and use request. So horizontal spindle barrel finishing has been developed and has good finishing effects for crankshafts with small size. But this process has bad uniformity for connecting rod journal of crankshafts with larger size by simulation experiments. Aimed at the size, shape and weight of crankshafts with larger size, theoretic research is done, and main factors for finishing uniformity are analyzed. Finally its finishing project is defined and experiments are done. The research indicates that this process is very effective for crankshafts with larger size, and has also positive influence on efficiency and auto product line.

New Electromagnetic Imaging Tool Introduced for Corrosion Detection

The new Electromagnetic Imaging Tool (EMIT) is introduced in this study. It is also described that the basic inspection theory, system structure and applications. The EMIT can determine whether metal loss or casing damage has occurred internally or externally. A 3D casing image can be supplied, including horizontal, vertical profile. The experimental results show that the EMIT has a “high-resolution” for MFL method in the casing well because of the steel brush structure. The minimal diameter of the inspection hole is 4 mm, and the thickness determination error of casing wall is 0.4 mm. A number of examples from oilfield are presented.

Research of Uniformity and Effect on Crankshaft Barrel Finishing

At present, crankshafts are finished mostly by abrasive cloth and manual steel brush, which is not ideal on finishing quality, efficiency, cost and cleanness degree. So a new process, horizontal spindle barrel finishing, is developed. Based on its finishing mechanism, factors and effect affecting finishing uniformity are analyzed by theory and experiment, finishing effect is defined, which provides basis for parameters selection of crankshafts barrel finishing.

Theoretic Analysis and Simulation on Horizontal Spindle Barrel Finishing

At present, crankshafts are finished mostly by abrasive cloth and manual steel brush, which is not ideal on finishing quality, efficiency, cost and cleanness degree. So a new process, horizontal spindle barrel finishing, is developed. By theoretic research and simulation, main factors for finishing effect and uniformity are analyzed. The research indicates that this process is very effective for crankshafts, and has also positive influence on efficiency and auto product line.

Surface Integrity Research on Barrel Finishing of Crankshafts’ Part

At present, crankshafts are finished mostly by abrasive cloth and manual steel brush, which is not ideal on finishing quality, efficiency and cost, especially cleanness degree does not meet design and use request. So a new horizontal spindle barrel finishing for crankshafts has been developed. To contrast the finishing effect, surface geometric characteristic, physical-mechanical property, cleanness degree etc. are analyzed, which indicates this process can comprehensively improve the surface integrity of crankshafts’ part. Simultaneously, this process can decrease cost, reduce labour intensity, improve efficiency, and easy to automation. Its application has wide economic and social benefits.

Process Characteristics Research on Horizontal Spindle Barrel Finishing

At present, crankshafts are finished mostly by abrasive cloth and manual steel brush, which is not ideal on finishing quality, efficiency and cost, especially cleanness degree does not meet design and use request. So horizontal spindle barrel finishing has been developed. Based on its finishing theory, process characteristics are key factors affecting the finishing effect, especially finishing uniformity. Process characteristics of motion parameters, finishing depth, finishing time, etc. are analyzed, and reasonable parameters are defined. It provides basis for industry application of this process.

Theoretic Analysis and Experimental Research on Barrel Finishing Uniformity of Crank Shafts with Larger Size

At present, crankshafts with larger size are finished mostly by abrasive cloth and manual steel brush, which is not ideal on finishing quality, efficiency and cost, especially cleanness degree does not meet design and use request. So horizontal spindle barrel finishing has been developed and has good finishing effects for crankshafts with small size. But this process has bad uniformity for connecting rod journal of crankshafts with larger size by simulation experiments. Aimed at the size, shape and weight of crankshafts with larger size, theoretic research is done, and main factors for finishing uniformity are analyzed. Finally its finishing project is defined and experiments are done. The research indicates that this process is very effective for crankshafts with larger size, and has also positive influence on efficiency and auto product line.