Analisis Lapisan Hard Chrome dengan Heat Treatment terhadap Kekerasan dan Struktur Mikro pada Permukaan Baja Karbon S45C

Generally, metals are easy to wear, so material modification is needed to increase hardness to increase the material's resistance to wear and tear. One way is to do a hard chrome plating process using the electroplating method and then continue the heat treatment process. This research was conducted to observe changes in the mechanical properties and microstructure of S45C steel that underwent hard chrome and heat treatment processes. This research was conducted by inserting S45C steel as a cathode into hard chrome liquid and using lead (Pb) as the anode. A positive (+) current powers the anode, the cathode has a negative current (-), the voltage used is 12 V with a duration of 60 minutes. After the cathode was coated with hard chrome, a hardness test was carried out, then continued with the heat treatment process using a temperature of 850°C for 30 minutes. The hardness test results show an increase in the hardness of S45C steel that has been coated with hard chrome, with a hardness value of S45C steel 202.70 VHN, S45C hard chrome steel 998.63 VHN. The highest hardness value is S45C steel coated with hard chrome 998.63 VHN, increasing 392.7%. Then the heat treatment process experienced a decrease in the hardness value, 528.90 VHN, with a percentage of 88.81%. The results of the microstructure observation showed that the hard chrome layer that had been heated treated showed even cracks in the hard chrome layer.

Influence of chrome electroplating on fatigue strength of parts

The article is devoted to the results of studies, which have been conducted on parts with electrolytic chromium in order to determine the effect of the coating on fatigue strength of their. The work was performed in observance of standards, which are fixed in GOST RV 2840-001-2008. Samples for the tests were made from standard gas turbine engine compressor blades. We used a VEDS- 1500 electrodynamic vibration stand with an UMK-12K power amplifier to excite vibrations. It has been shown that the minimum endurance limit of 46 kgf/mm2 based on 2 ∙ 107 cycles, established on uncoated parts, didn't decrease during fatigue tests of compressor blades with an electroplated chrome layer. It should be stressed that the influence of the geometry of the chrome-plated part on the reduction of the endurance limit has been established.

Experimental Study of Abrasive, Mechanical and Corrosion Effects in Ring-on-Ring Sliding Contact

This article presents the application of the ring-on-ring test to investigate some of the important factors affecting the abrasive and corrosion wear of a face seal used in the sugar industry. The test involves the sliding contact between two steel rings working in different conditions such as mechanic, abrasive, corrosive extortions and its combination. Rings were made of the C45 steel and the surface layers were modified by heat and thermochemical treatment such as normalizing, flame hardening, nitriding and chrome diffusion. Maximum wear of the sample after tests under mechanic, abrasive and corrosion extortion were obtained. For C45 steel without surface modification the biggest wear was obtained for mechanical, abrasive and corrosive extortion and equals 0.0138 g. This value was three times bigger than the result for the mechanical extortion and ten times than for the corrosive conditions. For individual research options the percentage increase or decrease in wear resistance in relation to the normalized surface layer was determined. In the corrosive extortion the highest increase (90%) of wear resistance was recorded for the chrome layer relative to normalizing sample. The main conclusion of the paper is that the wear effect caused by all factors—mechanical, abrasive and corrosive—is not a straight sum of values of wear.

Indentation hardness and modulus of electrochemically deposited triple protective-decorative Cu-Ni-Cr system

With respect to the corrosion-protective and decorative characteristics of the Cu-Ni-Cr systems the advance of the technology resulted in products covering the required technical and economic norms and indicators. However, the knowledge about the mechanical characteristics such as elastic and plastic properties of the individual layers and the whole multilayered system is still sparse. The objective of this study is to obtain by means of nanoindentation experiments the mechanical characteristics of standard triple Cu-Ni-Cr coating system whose morphology, structure, texture, composition, and the copper-, nickel- and chrome-layer thickness are predefined. A series of nanoindentation tests in vertical direction to the layered coating and in the lateral direction (along a vertical cut) is analyzed to assess the changes of the mechanical properties of the investigated system in depth and along the layer as well as at layer-to-layer and layer-to-substrate interfaces.

PENGARUH VARIASI KUAT ARUS LISTRIK DAN WAKTU PROSES ELECTROPLATING TERHADAP KEKUATAN TARIK, KEKERASAN DAN KETEBALAN LAPISAN PADA BAJA KARBON RENDAH DENGAN KROM

The usage of carbon steel at present is growing rapidly. The carbon steel is commonly used in the machining appliance and material construction, as well as oil or gas piping. Improvement of physical properties of steel can be performed by electroplating. The goal of this research was to prove the influence variation of strong electric current and processing time electroplating tensile strength, hardness and layer thickness on low carbon steel with chrome. The benefits of this research is to gain the information about a strong in fluence of electric current and time again sthardness and thickness of thetensile strength of low carbon steel with chrome plating.This research using low carbon steel coated by electroplating method with variations strong electric current 17.8A, 22.7A and 27.3A, and the length of processing 5, 10, and 15 minutes. The type of testing which done are to test the thickness, the hardness and tensile test. The processing of data were analyzed using analysis of variance two-way.Thickness layer of chrome increased along with increasing strong currents and the length of time coating. The highest value of the thickness chrome layer with strong currents occur in the calculation of 27.3A and with in 15 minutes of 0.00015 as well as microscope observation of 0.483 where there is a difference between calculation and observation microscope 400X magnification ranges from 99.9%. The highest hardness values obtained with strong currents 27,3A and within 15 minutes of 23,58 VHN or 12,621% harder compare with raw materials. For tensile test itself was increasing tensile strength with the highest value of 627.8 N / mm2 or 6.65% more than raw material.

Significant measureable development of inductance gain per unit of space in loop fractals

A significant measureable development of inductance gain per unit of space in loop fractals for a suite of inductors which occupy the same layout space and require only a single-fabrication layer is investigated. All structures are fabricated on a borofloat glass substrate with dielectric constant loss tangent of 0.004. A chrome layer of 30 nm for adhesion followed by a 180 nm gold layer were sputtered and etched. To increase the surface area is implemented a simple geometrical strategy through fractalization and consequently the inductive performances is improved. Also, the higher fractal orders can be developed the inductive performance over 9 times from 0th to 3rd order. The fractal derivations of the original loop due to its space filling properties are examined and it suggests that although the effective electrode length increases, overall, the arrangement still essentially occupies the same space. In terms of design space for 0th, 3O-5O-7O of 1st, 2nd, and 3rd orders of fractals, 0, 26.2, 34.6, 38.6, 65.5, and 75.8% of occupied conductor surface area are saved. The measured inductances and resistances for aforementioned orders of fractals are 4.6 nH and 5 Ω, 8.6 nH and 10.5 Ω, 12 nH and 11.6 Ω, 12.8 nH and 17.3 Ω, 19.2 nH and 23.2 Ω, and 44.7 nH and 63.5 Ω, respectively.

Design, Modeling and Optimization of a Novel Two DOF Polymeric Electro-Thermal Micro-Actuator

In this paper, design, simulation and optimization of a novel electrothermally-activated polymeric microactuator capable of generating combination of bidirectional lateral and rotational motions are presented. The composite structure of this actuator is consisted of a symmetric meandered shape silicon skeleton, a SU8 thermal expandable polymer and a thin film chrome layer heater. This actuator is controlled by applying appropriate voltages on its four terminals. With the purpose of dimension optimization, a numerical parametric study is executed. The modeled actuator which is 1560 μm long, 156 μm wide and 30 μm thick, demonstrates a remarkable lateral displacement of 23 μm at power consumption of 38 mW and a considerable rotation of about 7.5° at the same power consumption but with excitation of different terminals.