scholarly journals Analisis Pengaruh Variasi Arus dan Sudut Kampuh dengan Metode Pengelasan GTAW terhadap Sifat Mekanik dan Struktur Mikro Baja ST 41

2019 ◽  
Vol 2 (2) ◽  
pp. 39-50
Author(s):  
Ridhwan Haliq ◽  
Himawan Tri Raharjo

The objective of research is to determine the effect of welding current on the hardness, tensile strength, and microstructure from GTAW welding with ER70S2. This research used ST 41 low alloy steel material containing C = 0,16 %, Si = 0,23 %, Mn = 0,69 %, S = 0,031 %, P=0,019 %, yield point 40 kg/mm2, tensile strength 52 kg/mm2, dan elongation 32 %. ST 41 steel welding is carried out with current variations of 90 A, 110 A and 130 A with GTAW welding methode. Types of variation of the notch use are ][, V and X. The specimens was subjected to hardness, tensile strength, and metallography. Based on the result of hardness test with the factor elimination method in obtaining the angle ][ notch with current 90 A, V notch with current 90 A, and X notch with current 110 A. Tensile test results of the three materials, the highest tensile strength at the X notch with current 110 A is 416,8 N/mm2. The lowest tensile strength is obtained at welds with ][ notch is 360.73 N/mm2. From result of metallograph that we get if X notch with current 110 A is more stable, than ][ notch with current 90 A and V notch with current 90 A.

2014 ◽  
Vol 887-888 ◽  
pp. 824-829
Author(s):  
Qing Fang Lv ◽  
Ji Hong Qin ◽  
Ran Zhu

Laminated veneer lumber is taken as an object of study, and use LVL specimens of different sizes for compression test and tensile test. The goal of the experiment is to investigate the size effect on compressive strength and tensile strength as well as the influence of the secondary glued laminated face, which appears in the secondary molding processes. The results show that both compressive strength and tensile strength have the size effect apparently and the existence of the secondary glued laminated face lower the compressive strength of LVL specimens. Afterwards, the relationship between compressive strength and volume along with tensile strength and area are obtained by the test results.


2016 ◽  
Vol 842 ◽  
pp. 43-52 ◽  
Author(s):  
Viktor Malau ◽  
Latif Arifudin

Vickers microindentation hardness test has been applied for a long time to determine the mechanical properties of a small volume of samples. The procedure of this hardness test consists of using a constant load on a rigid indenter and measuring the dimensions of the indenter residual impression (indentation imprint) on the surface of the sample tested after loading and unloading. The objective of this research is to characterize the mechanical properties and material constants of HQ (High Quality) 705 alloy steel mainly its VHN (Vickers Hardness Number) and tensile strength before and after quenching and tempering heat treatments. The characterization is based on Vickers microhardness dependence load curves.Quenching treatment was performed in a furnace by heating the samples at austenite temperature of 850 o C with holding time of two hours and then the samples were rapidly cooled in oil bath. Tempering processes were conducted by heating again the quenching samples to temperatures of 150, 200, 250, 300, 350, 400, 450, 500, 550 and 600 o C with holding time of two hours for each sample. Finally, all samples were slowly cooled in atmospheric temperature. The mechanical properties of samples were characterized by using Vickers microhardness dependence load curves.The results show that VHN (Vickers Hardness Number) depends on indentation load and VHN increases with increment of load for indentation load lower than 5 N. VHN is almost constant for indentation load greater than 5 N. The raw material (without heat treatment) has the VHN and tensile strength of 3413 MPa and 1050.61 MPa respectively and the quenched samples have the VHN and tensile strength of 5407 and 1861 MPa respectively. The Vickers hardness and tensile strength decrease with the increment of tempering temperatures. The higher tempering temperature produces lower hardness and tensile strength. The raw material tensile strength of 1058.8 MPa obtained by tensile test is comparable to its tensile strength of 1050.61 MPa obtained by Vickers indentation. This result indicates that Vickers microindentation is valid to use for evaluating the tensile strength of HQ 705 alloy steel.


2012 ◽  
Vol 445 ◽  
pp. 213-218 ◽  
Author(s):  
Ahmet Koyun ◽  
Baris Koksal ◽  
Esma Ahlatcioglu ◽  
A. Binnaz Hazar Yoruc

The mechanical properties, among all the properties of plastic materials, are often the most important properties because virtually all service conditions and the majority of end-use applications involve some degree of mechanical loading [1]. In the present work three different commercial polyethylene materials are tensile tested at four or five different tensile rates and two or three temperatures. Tensile test results against tensile rate include stress at 0.5 % elongation, tensile strength, yield strength, modulus of elasticity, elongation at yield and % elongation are determined. It is concluded that the structure, chain lengths and branching rates of polymer matrix significantly effected tensile test curve characteristic.


2018 ◽  
Vol 9 (4) ◽  
pp. 560-571
Author(s):  
Hamed Hemmati Pourghashti ◽  
Malek Mohammad Ranjbar ◽  
Rahmat Madandoust

Purpose The purpose of this paper is to conduct a laboratory investigation on measuring the tensile strength of recycled concrete using a double punch test. Furthermore, one of the main goals of this study is to compare the tensile and compressive strengths of recycled concrete samples. Design/methodology/approach Recycled concrete samples were made with variables such as aggregate type (natural stone and aggregate recycled concrete), different water-to-cement ratios and different treatment conditions in the first stage. In the next stage, the double punch test was performed on them, and finally the results obtained from experiments were analyzed and investigated. Findings According to the above tests, it was concluded that: first, according to the laboratory results, the strength of concrete containing recycled aggregates becomes closer to the strength of concrete containing natural aggregates whenever the water-to-cement ratio is higher. Second, upon investigating the treatment conditions, it was observed that the treatment had a greater effect on the strength of the recycled concrete. However, this effect was less tangible in tensile strength. Third, upon investigating the results of tensile strength, it can be said that the Barcelona test results were closer to the direct tensile test results compared to the Brazilian test results. This indicates the higher viability of Barcelona’s test results. Fourth, the results obtained from the Barcelona tensile test for recycled concrete were closer to the results of the direct tensile test compared to the concrete containing natural aggregates, which suggests that the Barcelona test is more suitable as a tensile test for recycled concrete. Fifth, the effects of various factors on tensile strength were somewhat less compared to the compressive strength, although very close. Sixth, the relationships provided by the regulation for concrete tensile strength on compressive strength were highly inconsistent with the results obtained from the direct tensile test, for which the consistency was higher for concrete containing natural aggregates compared to recycled concrete. Seventh, the dispersion of results obtained from tensile tests was higher for recycled concrete compared to concrete containing natural aggregates, but lesser of this dispersion was observed in the compressive strength. Originality/value According to the laboratory results, the strength of concrete containing recycled aggregates becomes closer to the strength of concrete containing natural aggregates whenever the water-to-cement ratio is higher. Upon investigating the treatment conditions, it was observed that the treatment had a greater effect on the strength of the recycled concrete. However, this effect was less tangible in tensile strength. On the basis on the results of the tensile strength, it can be said that the Barcelona test results were closer to the results of the direct tensile test compared to those of the Brazilian test. This indicates the higher viability of Barcelona’s test results. The results obtained from the Barcelona tensile test for recycled concrete were closer to the results of direct tensile test compared to the concrete containing natural aggregates, which suggests that the Barcelona test is more suitable as a tensile test for recycled concrete. The effects of various factors on tensile strength were somewhat less compared to the compressive strength, although very close. The relationships provided by the regulation for concrete tensile strength on compressive strength were highly inconsistent with the results obtained from the direct tensile test, for which the consistency was higher for concrete containing natural aggregate compared to recycled concrete. The dispersion of results obtained from tensile tests was higher for recycled concrete compared to concrete containing natural aggregate, but lesser of this dispersion was observed in the compressive strength.


1999 ◽  
Vol 121 (2) ◽  
pp. 196-202
Author(s):  
M. Higuchi ◽  
T. Yamauchi ◽  
Y. Tanaka ◽  
K. Iida

The procedure for making crack starter weld deposit on drop-weight test (DWT) specimens was altered from two passes to one pass in about 1990. The effects of some parameters of crack starter weld process on drop-weight test results were studied. Results of this study indicated that length of overlap of the second pass and height of crack starter beads were most effective on nil-ductility temperature (TNDT). When overlap length and bead height of two-pass deposit were small enough, TNDT obtained by two-pass deposit became lower than one-pass TNDT, the discrepancy being by as much as 25°C. TNDT values for 24 Japanese steels were determined using two different DWT methods, one-pass deposit and two-pass deposit having small overlap length and bead height. The difference of TNDT depending on DWT method could be seen only for high-toughness low-alloy steel base metals. For other materials (i.e., low-to-medium-toughness low-alloy steel base metals, weld metals, and high-toughness carbon steels), TNDTS by two-pass and one-pass deposits were essentially the same. For lower-toughness steels, TNDT was frequently lower than the temperature of vTcv − 33°C), and thus, the reference nil-ductility temperature RTNDT was determined from Charpy impact test results. These results can be taken as a way of interpreting the past toughness evaluations made for operating plants using the two-pass TNDT.


2019 ◽  
Vol 18 (3) ◽  
pp. 297-306
Author(s):  
Cecep Slamet Abadi ◽  
Rosidi Rosidi ◽  
Idrus Assagaf

Welding technology is used because besides being easy to use, it can also reduce costs so it is cheaper. Especially for welding repair. From the welding repair the extent to which the strength of GMAW welds can repair components from the molded plastic mold room made of AISI 420 stainless steel. Repair of the print room components using deposit welding is tested using tensile strength and hardness as realization of resistance when holding the rate of liquid plastic entering the print room by 25 to 40 MPa, depending on the plastic viscosity, the precision of the mold and the filling level of the print room. Deposition welding method as a welding repair can affect a procedure to be able to produce a component that is safe and capable of being used in accordance with the provisions. The welding process used is reverse polarity GMAW DC with 125 A current and ER 70 S welding wire diameter 1.2 mm. Test material AISI 420. Tests carried out were tensile test, impact test and hardness test in weld metal, HAZ and base metal. From the Charpy impact test and tensile test obtained the value of welding strength which is close to the strength of the complete object, which is equal to 65%. The energy absorbed by the impact test object with GMAW welding is 5.4 Joule while for the whole test object is 8.1 Joule. The welding tensile strength is 520 MPa compared to the tensile tensile strength of 820 MPa.


2018 ◽  
Vol 7 (2.13) ◽  
pp. 394
Author(s):  
Muhammad Rafiq Yanhar ◽  
Muksin R Harahap ◽  
Ahmad Bachori ◽  
Suhardi Napid ◽  
Istu Sri Poneni ◽  
...  

The aim of this research is to know the fiber laminate adding effect to tensile strength, SEM photo, and hardness of teki grass (cyperus rotundus) composite specimen. Tensile and hardness test specimens were prepared by hand lay-up method with variations of 1, 2, and 3 fiber layers. Test results showed the highest tensile strength occurred in 1 layer fiber of 21.83 MPa and decreased in 2 layers of fiber and 3 layers of fiber of 17.95 MPa and 16.17 MPa. This is caused by random fibers that spread in all directions so that many fibers are not aligned with the tensile force. Addition of the fiber layer results in reduced resin volume so that the bond between fiber and matrix also decreases, which in turn will make the fiber cannot withstand tensile well. Analysis of SEM photographs also proves that the reduced volume of resin causes the bond between fiber and matrix to decrease resulting in cavities in 2 layer and 3 layers of composite. The results of the hardness test show that the addition of fiber layer decreases the hardness value. This is due to the soft grass fiber that is softer than the resin polyester, so that the added layer of fiber will reduce the hardness value.  


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