lojmikak
Dołączył: 30 Sie 2010
Posty: 1597
Przeczytał: 0 tematów
Ostrzeżeń: 0/5
Skąd: olvovw
|
 Wysłany: Pon 0:05, 03 Sty 2011 Temat postu: ugg italia 15CrMoR steel welded joints and mechani |
 |
|
15CrMoR steel welded joints and mechanical properties
Was conducted for the second test, the results shown in Table 2. The results showed that the measured tensile strength of joints were higher than JB4708.2000 standards, indicating that the weld has sufficient strength,[link widoczny dla zalogowanych], welded joint performance is good. From the joint macro-fracture situation, the fracture near the crack originated in the base metal at the fusion line and extend along the fusion line, eventually leading to fracture, the weld fusion zone of welded joints is the weak link. Analysis of the fracture surface showed that the central area of the fibrous fracture cross section, in the expansion process through a large plastic deformation. Check the tension off El, no breaks in the naked eye can see defects in the sample. Table 2 Tensile test results of welded joints (o'dMPa) Tab. 2Tensiletestresultofweldedjoints (o'b / MPa) No. 1 sample 2 sequence in the weld breaking off parts of 155O547 2,533,528 3,521,526 broken down in the weld in the weld-type impact test in JB30B impact testing machine, impact energy 30/15kg �� in The experimental results shown in Table 3. Can see that the impact of the weld zone above the heat affected zone properties to meet the requirements, that the impact of good performance of welded joints; relatively few impact test shows that, with the welding line energy increasing, the impact of performance degradation, which preheat temperature maximum, when the Table 3 the results of impact tests of welded joints x, J) Tab. 3ImpacttestresultofweldedjointsKIJ) specimen No. weld heat affected zone lll3lO6858O2lOllO38278398957679 preheat zone temperature of 15 to 190 ��, the impact absorbed energy the most. Welding specimen bending to 180. No cracking, indicating 15CIlMoR steel welded joint performance is good. 2.3 Metallographic examination tissue samples with an optical microscope. 15CrMo steel base metal of the Organization for fine pearlite + ferrite (Figure 2). The weld zone of welded joints for the columnar ferrite bainite (Figure 3),[link widoczny dla zalogowanych], the crystal from the center of the weld seam on both sides of the growth, and with the middle of the weld seam along the length of the columnar crystal growth case; heat affected zone for granular ferrite and granular bainite (Figure 4), the fine grain-based areas to granular bainite, while the distribution of acicular ferrite and a small amount of low-carbon martensite with high strength and toughness. The above analysis shows, 15CrMoR steel welding heat input should be strictly controlled. Heat input is too small, heat-affected zone temperature gradient increases, the cooling rate of hardening tendency of large, thereby increasing the tendency to cold cracking; heat input is too large and easy to heat-affected zone of coarse, resulting in embrittlement and heat affected zone softening phenomenon and reduce the joint strength and toughness. Figure 2 �� 1oo original microstructure of base metal weld zone of Figure 3, Figure 4 x500 base metal heat affected zone x500Fig. 2TheoriginalslructureofmaaJxxlO0Fig. 3Theslructureofweldzonex500Fig. 4TheHAZslructureofmalfixx5003 conclusion (3), JB4708-2000 requested by the tensile, impact, (1) According to the three groups of specimens after welding performance comparison shows, the best performance of a sample. Therefore 15CrMo steel welding, the use of preheating temperature is 150 ~ 190 ��, the welding current is 200 ~ 220A, arc voltage 22 ~ 25V, welding speed is 12 ~ 14cm/min,[link widoczny dla zalogowanych], layer temperature of 150 ~ 200 ��, and more Road, welding, after welding, after taking heat and high temperature tempering the welding process, the good performance of welded joints. (2) provided by JB4730.94 ray detection of the welded joints showed that the weld quality is not less than II, is no weld cracks, incomplete fusion and incomplete penetration defects. Bending tests showed that use of such welding process has been the mechanical properties of welded joints in full compliance with requirements. (4) The practical application shows that the welding process,[link widoczny dla zalogowanych], welding quality can meet the requirements. References: [1�� Su Haiqing. 15CrMoR steel welding [J]. Welding Technology, 2006. 35 (5) :63-64. [2�� Keyu Xiong, PROCEEDINGS, Yurong. 15CrMoR steel welding [J��. Welding Technology, 2004. 33 (3) :70-72. [3�� Chinese Mechanical Engineering Society Institute of Welding Code. Welding Manual (Volume II) [M��. Beijing: Mechanical Industry Press,[link widoczny dla zalogowanych], 1992. Tin \
相关的主题文章：
[link widoczny dla zalogowanych]
[link widoczny dla zalogowanych]
[link widoczny dla zalogowanych]
Post został pochwalony 0 razy
|
|
