機(jī)床鑄件缺陷修復(fù)技術(shù)的分析與研究

時(shí)間：2015/12/26 11:06:53 瀏覽量：444

通過對(duì)機(jī)床鑄件缺陷修復(fù)的幾種傳統(tǒng)修補(bǔ)方法的介紹及對(duì)各種方法不同特點(diǎn)的分析，確定機(jī)床鑄件缺陷修復(fù)局限性的存在原因。同時(shí)，對(duì)一種新出現(xiàn)的鑄造缺陷修復(fù)技術(shù)及其設(shè)備—鑄造缺陷修補(bǔ)機(jī)，進(jìn)行了實(shí)踐操作實(shí)驗(yàn)和試棒的顯微組織分析，說明用鑄造缺陷修補(bǔ)機(jī)修復(fù)機(jī)床鑄件缺陷是符合質(zhì)檢標(biāo)準(zhǔn)的，進(jìn)一步分析證明了缺陷修補(bǔ)機(jī)在鑄件缺陷修復(fù)方面是值得推廣的一項(xiàng)新技術(shù)。 關(guān)鍵詞：機(jī)床鑄件；修復(fù)技術(shù)；噴焊；電焊；修補(bǔ)膠；鑄造缺陷修補(bǔ)機(jī)。

通過對(duì)幾種傳統(tǒng)焊補(bǔ)工藝在機(jī)床鑄件缺陷處的修補(bǔ)結(jié)果，分析機(jī)床鑄件修復(fù)結(jié)果不佳的原因。通過對(duì)鑄造缺陷修補(bǔ)機(jī)在機(jī)床鑄件的修復(fù)結(jié)果的研究，確定一種確實(shí)可行的在機(jī)床鑄件上修復(fù)的新技術(shù)及其工藝。

傳統(tǒng)焊補(bǔ)工藝的焊補(bǔ)結(jié)果及分析

材質(zhì)HT200，導(dǎo)軌缺陷處面積S＜1000mm2，深度h＜8mm。熱處理狀態(tài)：3件未進(jìn)行表面淬火，1件已表面淬火。用鎳基焊粉F103，電弧焊用鑄鐵焊條：Z308、Z248。

噴焊設(shè)備，電弧焊設(shè)備，鎳基焊粉F103（C≤0.15 8.0＜Cr＜12 2.5＜Si＜4.5 1.0＜B＜1.7 Fe≤8其余Ni），鑄鐵焊條：Z308，Z248。 

1、噴焊

按噴焊工藝執(zhí)行，將導(dǎo)軌面預(yù)熱至150℃以上，完成初步焊粉的噴涂后，將噴涂面加熱至900℃-1200℃以上，使焊粉熔化后形成平整面。由于預(yù)熱及加熱時(shí)間長(zhǎng)，工件受熱面積較大，熱應(yīng)力較大，比電弧焊更容易產(chǎn)生裂紋，同時(shí)線收縮產(chǎn)生裂紋傾向更大。由于裂紋傾向受噴焊時(shí)間、噴層厚度等因素影響，缺陷大小受到一定限制，而且焊補(bǔ)的缺陷需清理干凈，由于噴粉中含F(xiàn)e量比例較高，形成的噴層較電弧焊與母材的顏色更相近。但因具有一定量的Ni，所以無法與母材顏色更接近，焊補(bǔ)后可以進(jìn)行機(jī)械加工。 

2、電弧焊

用鑄鐵焊條Z248進(jìn)行焊補(bǔ)，焊補(bǔ)工藝分兩種，第一種：焊前預(yù)熱至550℃-650℃，焊補(bǔ)后保溫5-8小時(shí)；第二種：工件焊前不預(yù)熱，焊后保溫3-4小時(shí)。兩種方法均易出現(xiàn)裂紋、硬點(diǎn)，焊補(bǔ)后不容易進(jìn)行機(jī) 械加工。焊條價(jià)格便宜。 用鎳基鑄鐵焊條Z308焊條焊補(bǔ)，焊層與焊層之間應(yīng)停頓冷卻至60℃以下，焊補(bǔ)區(qū)少氣孔、裂紋產(chǎn)生，機(jī)械加工性良好，結(jié)合強(qiáng)度高、無脫落現(xiàn)象，由于機(jī)床導(dǎo)軌加工后吸油及焊條吹力的影響，易產(chǎn)生咬邊、形成“焊補(bǔ)痕跡”，焊補(bǔ)區(qū)顏色與母材有很大區(qū)別，而且焊條價(jià)格昂貴。 

3、結(jié)果分析

傳統(tǒng)的噴焊、電弧焊工藝，焊補(bǔ)后易產(chǎn)生裂紋，工件易受熱變形，容易出現(xiàn)二次氣孔，焊補(bǔ)處金屬顏色與母材差異大是其共同的特點(diǎn)，這也是傳統(tǒng)焊補(bǔ)工藝不能徹底解決機(jī)床導(dǎo)軌缺陷修復(fù)的根本原因。

Through the introduction of several traditional repair methods for the repair of machine tool casting defects and the analysis of different characteristics of various methods, the existence of the limitations of machine tool casting defect repair is determined. At the same time, for a new casting defect repair technology and its equipment-casting defect repairing machine, the practical operation experiment and the microstructure analysis of the test bar are carried out, which shows that the repair of the machine tool casting defect by the casting defect repairing machine is in compliance with the quality inspection standard. Further analysis proves that the defect repairing machine is a new technology worthy of promotion in the repair of casting defects. Key words: machine tool castings; repair technology; spray welding; electric welding; repair glue; casting defect repair machine.
Through the repair results of several traditional welding repair processes in the defects of machine tool castings, the reasons for the poor repair results of machine tool castings are analyzed. Through the research on the repair results of the casting defect repairing machine in the machine tool casting, a new technology and its technology for repairing on the machine tool castings are determined.
Welding repair results and analysis of traditional welding repair process
Material HT200, the area of the guide rail defect is S<1000mm2, and the depth h<8mm. Heat treatment state: 3 pieces were not surface hardened, and 1 piece was surface hardened. Nickel-based solder powder F103, cast iron electrode for arc welding: Z308, Z248.
Spray welding equipment, arc welding equipment, nickel-based solder powder F103 (C ≤ 0.15 8.0 < Cr < 12 2.5 < Si < 4.5 1.0 < B < 1.7 Fe ≤ 8 remaining Ni), cast iron electrode: Z308, Z248.
1, spray welding
According to the spray welding process, the surface of the guide rail is preheated to above 150 ° C. After the initial welding powder is sprayed, the sprayed surface is heated to above 900 ° C - 1200 ° C to form a flat surface after the solder powder is melted. Due to the long preheating and heating time, the workpiece has a large heating area and a large thermal stress, which is more likely to cause cracks than arc welding, and the tendency of the line shrinkage to generate cracks is greater. Since the crack tends to be affected by factors such as spray welding time and thickness of the spray layer, the size of the defect is limited, and the defects of the weld repair need to be cleaned. Due to the high proportion of Fe in the dust spray, the sprayed layer formed is more arc welded than the mother. The color of the material is more similar. However, since it has a certain amount of Ni, it cannot be made closer to the color of the base material, and can be machined after welding.
2, arc welding
Welding repair with cast iron welding rod Z248, the welding repair process is divided into two types, the first one: preheating to 550 ° C -650 ° C before welding, 5-8 hours after welding repair; second: the workpiece is not preheated before welding, After welding for 3-4 hours. Both methods are prone to cracks and hard spots, and it is not easy to machine after welding. The electrode is cheap. With nickel-based cast iron welding rod Z308 welding rod welding, between the welding layer and the welding layer should be cooled to below 60 °C, the welding area is less pores, cracks, good mechanical workability, high bonding strength, no shedding phenomenon, due to machine tool guide After the processing, the influence of oil absorption and welding rod blowing force is easy to produce undercut and form "welding marks". The color of the welding area is very different from that of the base metal, and the welding rod is expensive.
3. Analysis of the results

The traditional spray welding and arc welding processes are prone to cracks after welding, the workpiece is susceptible to thermal deformation, and secondary voids are prone to occur. The difference between the metal color and the base metal at the weld repair is common. This is also the traditional welding repair process. Completely solve the root cause of machine tool guide defect repair.

http://zhuoyuanjixie.com