The Structure Analysis And Welding Technology Research For The Mast Of NR220 Rotary Drilling Rig

Rotary Drilling Rig is a kind of equipment with large power.Because the terrain of construction site is so complex and the geology condition of is very different,the operation condition is very complicated and easily changeable,which causes many problems to solve hardly.For example,the mast becomes deformed and crack,the equipment capsizes,the Kelly bar jammed,etc.At present,the quality and technical capability can not be satisfied the user.So it is extremely urgent to do the research and analysis for Rotary Drilling Rig.At the same time,it is necessary for it to accelerate its development and localization in our country. The choice of this paper is based on the NR220 Rotary Drilling Rig project which developed by the Inner Mongolia North Hauler Joint Stock company and JiLin university.The mast is the key part in the whole Drilling Rig and its structure is very important.It provides the support and guide function to the Kelly bar,sustains Kelly bar to realize the accurate location of stake hole.It should has good rigidity and steady character,anti-impact,endure evibration.In our country,there are few factorIies to independently research and produce Rotary Drilling Rigs.The Rotary Drilling Rigs in our country which are on sale are introduced from abroad,so the reference documents about the design calculation of Rotary Drilling Rig are limited.When designing the Drlling Rig in our country,the actual structure still uses the method that integrates traditional materials mechanics with experience design.Although the reliability of this method is proved by practice,it also has many abuses.Firstly,using this ways need a long design period,and according to the materials mechanics theory and simplistic experienced formula finish the manual calculation,then arrange the bolster according to the result.This takes a lot of time and it is difficult to ensure the design veracity.Secondly,the structure components which are based on traditional design are so redundance,the uses of materials tend towards conservation.so the weights of same products are much heavier than the abroad′s.The result not only causes higher cost and lower benefit,but also weakens the competition of products. Recently years,the Drilling Rigs in our country have made rapid progress,but the whole technique levels are not high.Especially in the aspect of structure design and manufacture,because Rotary Drilling Rigs have special construction methods and structure feature,the requirements to the structures are very strict.The work stability of structures directly affect the work time and efficiency of the whole machine.So it is very significant that reasonably design the dimension of structure,do the simulate analysis and best design,discuss the manufacture technology of large-scale structure and research the design method of welding tooling to enhance the whole design and manufacture level of Drilling Rig trade of our country.Especially the lack of accurate comprehension to the machine at the beginning of NR220model machine test,the accident of mast break happened during the test.for this reason ,it is very urgent to do the research of welding procedure and finite element analysis for the mast. In the first place,this paper verify the mast including axle load ,steady-state performance,rigidity,the acting force which is brought by bending and twisting with compressing and bending together,the power stress which is caused when the rotary drive slides on it,twisting stress.the result is that the structure design of mast satisfy the requirement of safety.At the same time,after analyzed ,this paper made a conclusion that the main reason of mast crack was not the material and manufature technology,but was the driver′s wrong operation. This paper also uses the finite element software to analyze the mast because of the limitation of theoretical calculation.According to the process of Pro/MENCHANICA Wildfire software,this paper firstly builds the 3D-model for the mast with the Pro/ENGINEER Wildfire software,and simplifys the model to save time,then uses the AUTOTEM function to divide the web for the finite element model.After finish the material definition ,boundary restraint condition definition,the paper begins to establish the analysis tast to calculation.At last,the paper displays the stress distributed picture with two ways and gets the true result.We clearly know the stress level and strain condition of the key part structure and find the weak position through the finite element analysis.We also improve the structure of mast based on the abovetheoretical calculation and finite element analysis. Rotary Drilling Rigs must have strong structure and reliable functions depended on its work conditions.They are large-scale structure and the manufacture precision and reliable have large influence on their functions, use life,reliability of the whole machine.They stands for the manufacture level of a enterprise.So this paper also undertakes to prevent the mast crack and welding deformation to research the welding technology for mast of NR220 Rotary Drilling Rig.Through this job,we not only get the factor which affect the welding quality of the large-scale structure like mast,but also get the solutions how to prevent the welding crack,welding stress and welding deformatio.All of these solve the specific production problems and advance the enterprise to improve the whole welding manufacture level.That is very effective. This paper researches the right concept and principle of the welding tooling to be aimed at the structure feature and manufacture of mast.This paper also introduces the principle,structure and the practical application situation in our company,which provide the experience of guiding our welding tooling design. To our company , Rotary Drilling Rigs are completely new products.There is no any experience as reference.Especially we met a lot of difficulties during we design and manufacture the large-scale structure like mast assembly and frame assembly.Therefore we can not but validate and check the rationality of intension,rigitidy and structureby the way of manufacture the model machine for these large-scale components.This not only prolongs the period which the products enter into the market,but also increases the design difficulties and workload.This paper adopts the way integrates theoretic calculation with finite element to analyze the mast structure,which leads the forward position in this area.At the same time,researching the welding procedure of mast has solved the deformed problem during the mast process of building,which not only enhances manufacture level and production quality,but also supplies a reference for this field and expedites the localization of Rotary Drilling Rig.