振动筛用焊接棒条筛板的开发研究

发布时间：2019-07-02 19:34

【摘要】：在冶金、煤矿、矿山、水泥等行业大量使用各种振动筛分设备,而筛板是保证振动筛能否正常使用的关键配件之一。棒条筛板是近几年出现的一种新型筛板,这种筛板使用弹簧钢作为主要部件。现有结构如下：弹簧钢棒条一端穿入预先打有安装孔的方形空心钢内,用压条压紧固定,另一端为自由悬空状态,可以自由振动。这种筛板在实际生产中存在两个主要问题：筛板制作过程中先在角铁上钻孔,再把角铁焊到一起,这样可能造成筛板上的两个孔不在一条直线上,对于穿棒条造成一定困难；或是导致安装不便,或是导致安装固定不可靠,造成筛板在工作过程中出现松动断裂等意外情况。 本文研究一种新型振动筛用焊接棒条筛板,这种筛板是把尺寸一定的弹簧钢棒条按照有关尺寸要求直接焊在钢板上,从而解决前述的棒条穿孔安装工艺的问题。棒条需要具有高的屈服强度和疲劳极限以保证筛板的耐磨性能和抗疲劳断裂能力,而筛板框架性能要求韧性和焊接性良好。因此棒条材料选弹簧钢,筛板框架材料选普通碳素结构钢。这两种材料之间的焊接属于异种钢之间的焊接,由于异种钢的化学成分和物理性能等存在较大的差异,使其之间的焊接较为困难,如果工艺控制不好,会增加焊缝及热影响区的淬硬程度,降低焊接接头的抗裂性；焊接区域和被焊工件温度差增大,使焊接应力增加、焊接应变速率增大,导致焊接裂纹更容易产生；会使焊缝和热影响区中的氢不易逸出,使裂纹产生的概率增大。本文通过研究65Mn、60Si2Mn、60Si2CrV三种弹簧钢棒条与Q235钢板的焊前预热和焊后热处理工艺,来改善焊接接头的性能。主要内容包括：根据母材成分确定焊条成分；焊接前母材进行200℃、300℃、400℃的预热,预热时间为30min；焊接后立即在200℃、250℃、300℃、350℃、400℃、450℃回火,回火时间为2h。利用金相显微镜观察每个试样的显微组织结构,分析不同工艺下组织的变化；洛氏硬度机测定每组试样的焊缝不同区域的硬度,疲劳试验机测定不同工艺下筛板棒条的使用寿命,通过组织、硬度、疲劳寿命综合分析材料组织对性能的影响,得出最佳的热处理工艺。 试验结果：用于焊接弹簧钢和碳素结构钢的焊丝选用结506低氢钾型焊丝；用三种弹簧钢焊接筛板是最佳预热温度为300℃,保温时间为30min,回火温度为450℃,保温时间为2h。 为了满足实际生产和经济性要求,对比三种材料。发现65Mn弹簧钢制成的筛板疲劳寿命最短,60Si2Mn制成的棒条筛板次之,60Si2CrV制成的筛板最好。但从经济性和实用性能两方面考虑,60Si2Mn制成的筛板成本较低,但能满足生产要求。 采用最佳焊接工艺,把用60Si2Mn制成的筛板应用到矿山机械上,与原结构的筛板使用寿命近似,都在三个月以上。
[Abstract]:A variety of vibration screening equipment is widely used in metallurgy, coal mine, cement and other industries, and screen plate is one of the key accessories to ensure the normal use of vibrating screen. Bar screen plate is a new type of screen plate which appears in recent years. Spring steel is used as the main component of this kind of screen plate. The existing structure is as follows: one end of the spring bar is pierced into the square hollow steel with pre-installed holes, and the other end is freely suspended, which can vibrate freely. There are two main problems in the actual production of this kind of screen plate: first, the angle iron is drilled in the process of screen plate making, and then the angle iron is welded together, which may cause the two holes in the screen plate not in a straight line, which may cause some difficulties for piercing the rod bar, or lead to the inconvenience of installation, or the unreliable installation of the screen plate, resulting in loosening and fracture of the screen plate in the course of work. In this paper, a new type of welded bar screen plate for vibrating screen is studied. The screen plate is to weld the spring steel bar with a certain size directly on the steel plate according to the relevant size requirements, so as to solve the problem of the above mentioned rod and bar piercing installation process. The bar needs high yield strength and fatigue limit to ensure the wear resistance and fatigue fracture resistance of the screen plate, while the frame performance of the screen plate requires good toughness and weldability. Therefore, the rod material is spring steel and the screen plate frame material is common carbon structure steel. The welding between the two materials belongs to the welding between dissimilar steel. Because of the great difference in chemical composition and physical properties of dissimilar steel, the welding between dissimilar steel is more difficult. If the process control is not good, the hardening degree of weld and heat affected zone will be increased, and the crack resistance of welded joint will be reduced. With the increase of the temperature difference between the welding area and the welded workpiece, the welding stress and the welding strain rate are increased, which leads to the welding crack is easier to occur, and the hydrogen in the weld and heat affected zone is not easy to escape and the probability of crack is increased. In this paper, the preheating and post-weld heat treatment processes of 65mn, 60Si2Mnand 60Si2CrV spring steel bars and Q235 steel plates are studied to improve the properties of welded joints. The main contents include: determining the composition of electrode according to the composition of base metal; preheating the base metal at 200 鈩，

本文编号：2509171