Metal structures of the mining equipment are made of a steel with good weldability and mechanical characteristics corresponding and namely St 52.3 steel that allows the use of these metal structures in heavy duty. Metal structures of the mining equipment are very large structures and strong requested mechanical, and in these conditions during exploitation can occur large deformations at these that may cause a decrease in the exploitation safety of mining equipment. Research has followed in principal the analyze of deformations appear in metallic structures, and for realizing the researches has been used both a dimensional analysis and one that is based on the finite element method

D. Dobrotă

G. Paraschiv

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657METALURGIJA 53 (2014) 4, 657-660G. PARASCHIV, D. DOBROTĂRESEARCH ON DEFORMATIONS WHICH APPEAR IN WITHIN THE METAL STRUCTURES OF MINING EQUIPMENTReceived – Prispjelo: 2014-01-17Accepted – Prihvaćeno: 2014-05-15Preliminary Note – Prethodno priopćenjeISSN 0543-5846METABK 53(4) 657-660 (2014)UDC – UDK 669.11:620.178:620.193=111G. Paraschiv, Department of Biotechnical Systems, Biotechnical Systems Engineering Faculty, Polytehnic University of Bucharest, RomaniaD. Dobrotă, Department of Engineering and Management of Tech-nological Systems, Engineering Faculty, University “Constantin Brâncuşi” Târgu-Jiu, RomaniaMetal structures of the mining equipment are made  of a steel with good weldability and mechanical characteristics corresponding and namely St 52.3 steel that allows the use of these metal structures in heavy duty. Metal structures of the mining equipment are very large structures and strong requested mechanical, and in these conditions during exploitation can occur large deformations at these that may cause a decrease in the exploitation safety of mining equipment. Research has followed in principal the analyze of deformations appear in metallic structures, and for realizing the researches has been used both a dimensional analysis and one that is based on the finite element method.Key words: metal structures, deformations, dimensional analysis, finite element methodINTRODUCTIONEvaluation and knowledge of deformations which appear in the metallic structures of the mining equip-ment is particularly important to assess their lifetime. Metallic construction used at mining equipment are welded metallic construction which must provide a ser-vice life as big as possible. [1]. A big problem of equipment is the welded metallic construction which over time has not been modernized but suffered only some repairs. The life of welded metal-lic construction of the mining equipment is very much influenced by the evolution of deformation suffered by them. Deformations suffered by metallic construction are caused by very high mechanical requests, but also be-cause phenomena of corrosion and dimensional change which appear by redistributing material, and they all ap-pear after a certain period of exploitation. Welded metal constructions have become increas-ingly popular in recent years, within the mining equip-ment, because of the advantages they have in compari-son with other structures obtained by other technologi-cal processes. Through its specificity, the process of achieving products in welded constructions presents a number of disadvantages arising primarily from work-ing with liquid materials [3].Welded metal constructions used in mining exploita-tion are very strong mechanically requested, but at the same time they are subject to the action of specific agents of working environment [4]. The life of these welded me-tallic construction is very much influenced by the evolu-tion of size and deformation suffered by them. Thus an important analysis which must be realized  relates to the evolution of the deformations that occur within the weld-ed metallic construction, and determining principal causes that cause these deformations [5].Construction steels for general use, type St 52.3, compared with carbon steels, have become widely used in construction machineries in the mining exploitation, due to the characteristics they have and allow a proper behavior of complex requests combined with action of corrosive working environment [6].Welded metal constructions used in the mining of coal are cyclic requested at fatigue, but also works in a chemically aggressive environment. The aggressive-ness of the environment in which the construction work can be explained by the presence in the atmosphere of large quantities of chemicals that can act as an aggres-sive environment [7]. Aggressive working environment is characterized mainly by the presence in the atmosphere of large quan-tities of sulfur from emissions from the local power plants. The apparition of corrosion within metallic structures cause a change in the size of the metal build-ing, and this influence the occurrence of phenomena by the type of deformations [8].Also it should be considered the fact that in the met-al construction of mining equipment is a random distri-bution of efforts and thus should be considered all the possibilities of requests that may arise.MATERIALSResearch has primarily aimed to determine the de-formations that occur in metallic structures made  of steel St 52.3, and to do research it must be used a di-mensional analysis, and an analysis using the finite ele-658  METALURGIJA 53 (2014) 4, 657-660G. PARASCHIV et al.: RESEARCH ON DEFORMATIONS WHICH APPEAR IN WITHIN THE METAL STRUCTURES...ment method. The research was focused on those weld-ed steel constructions that have been used a long time and through this analysis it was aimed to establish pos-sibilities which are for the safe use of such metallic con-structions. The use of this steel is indicated at the fabri-cation of resistance elements (beams, columns, sections, rails, brackets, etc.). Defects which appeared during operation are deter-mined by the incognizance of technological aspects , but also the use of materials with inadequate for pur-pose. Among the factors that have influence on the life of welded metal constructions are mentioned: the choice of materials and welding processes, chemical composi-tion, thermal influence zone, etc. To achieve desired re-sults in the research, it was initially determined the chemical composition for steel St 52.3 which is present-ed in Table 1.Table 1 The chemical composition of the steel St 52.3 / %C Mn Si S P Al Ni Cr0,136 1,22 0,365 0,017 0,017 0,011 0,022 0,027For St 52.3 steel is recommended that up to a thick-ness of 10 / mm of pieces,they must not preheat, be-cause welding linear energy realize a sufficient preheat-ing for welding operation.Analyzed metallic construction “excavator arm ERc 1300” is obtained from the highlights of rolled St 52.3 steel with thickness of 10 / mm, positioned and assem-bled by manual welding with basic electrodes.RESULTS AND DISCUSSIONSTo realize the research was ralized initial a drawing of the excavator arm which is partially shown in Figure 1, and in this drawing were established primarily the dimensions component pieces and the arrangement and combination of them.Experimental research made at different time have shown that in the KL constructive element (Figure 1) of the excavator arm were occurred deformities increas-ingly larger, and this may cause deformation or break-age of the entire metal construction of excavator . These deformations can be determined by changing the mate-rial properties of the metal structure or appearance of intergranular corrosion phenomena and high mechani-cal requests. Thus in the first phase of experimental re-search it was visually analyzed the deformations area and were not found superficial corrosion areas where is currently a continuously coating layer Figure 2. Also, the method of deforming the excavator arm element is shown in Figure 3.Due to the lack of a visible surface corrosion in the next step we aimed to determine possible corrosion phenomena that may occur under the paint and can af-fect the metal structure. To identify these corrosion phe-nomena it was used in the experiments LAPTOSCOP Figure 1  Partial description of shape and dimensions of the excavator armFigure 2 The deformed element of the excavator armFigure 3  The mode of deformation of the excavator arm element659METALURGIJA 53 (2014) 4, 657-660G. PARASCHIV et al.: RESEARCH ON DEFORMATIONS WHICH APPEAR IN WITHIN THE METAL STRUCTURES...type apparatus that allows non-destructive determina-tion of thickness of paint and oxides and thus can estab-lish the thickness of metal that is in that structure.The experiments were performed by making several measurements (18 measuring points) points along the metal piece KL, and the obatined results are presented in Table 2.Table 2  Thicknesses determined after measurements performed on the deformed element / mmNo. Thickness of the deformed elementThe thickness of the paint and oxidesMetallic mate-rial thickness1 10,96 0,967 9,9932 10,95 0,969 9,9813 10,92 0,967 9,9534 10,91 0,965 9,9455 10,90 1,001 9,8996 10,91 1,108 9,8027 10,89 1,147 9,7438 10,92 1,167 9,7539 10,91 1,283 9,62710 10,93 1,288 9,64211 10,89 1,295 9,59512 10,96 1,152 9,80813 10,94 1,038 9,90214 10,93 0,984 9,94615 10,96 0,967 9,99316 10,96 0,961 9,99917 10,95 0,959 9,99118 10,94 0,952 9,988From the results shown in Table 2 it can be observed the fact that the thickness of the KL element is approxi-mately 10,9 / mm, and this size is formed from a layer of paint and oxide plus the thickness of the metal part. After the measurements was found that in the area of points 9 ÷ 11 is the thickest layers of paint and oxides, and in this area there is the smallest thickness of the metal layer , namely the thickness is reduced by 5-6 / % in relation to the new state. In these conditions it was observed that int his area the maximum deformation which extend and has an increasing length.To determine the causes of deformation of the KL structural element that have been considered and some of it blows received during the operation and that could produce a strain accidentally . It was also taken into ac-count this hypothesis given the shape deformation which occurred. Research has shown that the appear-ance of the deformation due to a hit is highly unlikely and in these conditions was switched to another method to confirm the results obtained in experimental research, namely the finite element method.Determining the deformation parameters by conven-tional analytical methods is not possible for massive spatial structures. Excavator arm ERc 1300, is a mas-sive spatial structure which can be studied using finite element method using a process of discretization, name-ly h-element method. Discretization was done with sec-ond order tetrahedral elements. These elements are used for good discretization with small errors on curved sur-faces. The third-order elements used at discretization of spline curves and surfaces generated in this way.To study it was used Autodesk Inventor 2011 program running on an Intel QuadCore 3.5 GHz computer. The ap-plication method of loads on the metal structure is shown in Figure 4, and the values  of loads after the three direc-tions OX, OY respectively OZ are shown in Table 3.Table 3 Operating conditions,  Force:1 / NLoad Type ForceVector X 0,000Vector Y -300 000,000Vector Z 0,000To apply the Finite Element Method it is necessary to be known in great detail the physical properties of the metal structure analyzed and a detailed presentation of them is presented in Table 4. Analyzing the physical properties of the metal structure analyzed is can be ob-served the fact that it has a very large load, and a fairly large area which demonstrates once again the complex character metal of the analyzed structure.Table 4  The physical properties of the metal structure analyzedMaterial DefaultMass 2 072,59 / kgArea 61 888 500 / mm2Volume 2 072 590 000 / mm3Center of Gravity x=14 783,613 / mm, y=1 523,341 / mmz=59,055 / mmAlso, Finite Element Analysis of steel structures is possible if physical and mechanical properties of the material which is made are known, and the analyzed case the material was steel St 52.3 with the properties shown in Table 5.Application of Finite Element Method for metallic structure analyzed is realized only after initially have been realized some advanced settings fot the applied fi-nite element and setting values  performed are presented in Table 6.Figure 4 The application of loads on steel structure660  METALURGIJA 53 (2014) 4, 657-660G. PARASCHIV et al.: RESEARCH ON DEFORMATIONS WHICH APPEAR IN WITHIN THE METAL STRUCTURES...Table 6 Advanced settingsAvg, Element Size (fraction of model diameter) 0,1Min, Element Size (fraction of avg, size) 0,2Grading Factor 1,5Applying the load on metal structure cause some re-actions of force type or the moment within constraints made , and the values  obtained for them by applying the finite element method are presented in Table 7.Table 7 Reaction force and moment on constraintsMagnitude/ NComponent (X,Y,Z) / NMagni-tude / N·mComponent (X,Y,Z)/ N·mFixed Constraint:1 96 907,7294 011,112 106,493-15,88-23 515,5 -105,31186,792 0Fixed Constraint:2 336 616-94 026 68,26733,69323 217 -59,370 0 Application of finite element method for the analy-sis of metal structure allowed obtaining both numerical values  for the deformations obtained on the element structure, Table 8, and highlighting the ways in which the deformation and its shape are produced is shown in Figure 5.Table 8 Result SummaryName Minimum MaximumVolume 2 072 590 000 / mm3Mass 16 290,5 / kgVon Mises Stress 0,091 / MPa 46,007 / MPa1st Principal Stress -1 010,573 / MPa 36,901 / MPa3rd Principal Stress -39,856 / MPa 7,041 / MPaDisplacement 0 / mm 2,963 / mmSafety Factor 4,499 / ul 15 / ulX Displacement -1,722 / mm 0 / mmY Displacement -2,422 / mm 2,46 / mmZ Displacement -0,263 / mm 0,011 / mmCONCLUSIONSFollowing experimental research and modeling car-ried out by finite element method we can draw the fol-lowing conclusions:-  welded construction of mining process equipment are strongly mechanically requested, but at the same time and are subjected to corrosion;-  metallic construction of mining equipment are com-plex structures whose modeling by finite element allows obtaining significant results;-  deposition of coatings of paint that has lower protec-tion features on metallic construction causes metal corrosion phenomena in depth metal structure;-  deformation structures are determined by mechani-cal actions, but they are enhanced by corrosion phe-nomena which cause a reduction in the thickness of metallic material;-  application of the finite element method allows high-lighting areas where are produced maximum defor-mations of structures, but also allows for confirma-tion of the results obtained in experimental research;-  deformations occur mainly in the case of those struc-tural elements that have horizontal position in the metal structure and in this regard it is recommended to adopt constructive changes, and adoption of heat and thermochemical treatments that increase resist-ance to deformation of them;-  adopting appropriate technological solutions can cause accidental occurrence of large deformations, and if one takes into account the complexity of the hardware and repair costs are very high.REFRENCES[1]  D. Dobrotă, Metalurgija, 53 (2014) 2, 179-182. [2]  C. Babis et al., Metalurgija, 53 (2014) 2, 251-253. [3] L. Henning et al., EPA contract no, 68-Do-123, Midwest Research Institute, Kansas City, (1994).[4]  ANSI Z49.1, Section E5.4 pp. 12, American Welding So-ciety, 550 NW LeJeune Road, Miami, FL, 2005.[5]  Y, Wang et al., Materials Environ, Sci, Technol, 45 (2011) 15, 6539-6544.[6]  B. Chang et al., Journal of Materials Processing Technolo-gy 108 (2001) 3, 307-313.[6]  E. Bayraktar et al., Journal of Materials Processing Tech-nology 145 (2004) 1, 27-39.[7]  O. Chivu, Metalurgija, 52 (2013) 4, 465-468.[8]  D. Dobrotă, L. M. Cîrtînă, Proceedings of a Conference “Modern Technologies Quality and Restructuring – TMCR”, Chişinău, (2005) 2, 377-380.Note:  The responsible translator for English language is DELTRA CELES SRL, Bucharest, RomaniaTable 5 Physical and mechanical properties of steel St 52.3Name Steel, MildGeneral Mass Density 7,86 / g/cm3Yield Strength 207 / MPaUltimate Tensile Strength 345 / MPaStress Young’s Modulus 220 / GPaPoisson’s Ratio 0,275 / ulShear Modulus 86 274,5 / MPaFigure 5  The mode of deformation of the metal structure obtained by applying the finite element method

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Research on deformations which appear in within the metal structures of mining equipment

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657 METALURGIJA 53 (2014) 4, 657-660G. PARASCHIV, D. DOBROTĂRESEARCH ON DEFORMATIONS WHICH APPEAR IN WITHIN THE METAL STRUCTURES OF MINING EQUIPMENTReceived – Prispjelo: 2014-01-17Accepted – Prihvaćeno: 2014-05-15Preliminary Note – Prethodno priopćenjeISSN 0543-5846METABK 53(4) 657-660 (2014)UDC – UDK 669.11:620.178:620.193=111G. Paraschiv, Department of Biotechnical Systems, Biotechnical Systems Engineering Faculty, Polytehnic University of Bucharest, RomaniaD .  D o b r o tă,  D ep artm en t  o f  E n gin eerin g  an d  M ana g em en t  o f  T ec h -nological Systems, Engineering Faculty, University “Constantin Brâncuşi” Târgu-Jiu, RomaniaMetal structures of the mining equipment are made   of a steel with good weldability and mechanical characteristics corresponding and namely St 52.3 steel that allows the use of these metal structures in heavy duty. Metal structures of the mining equipment are very large structures and strong requested mechanical, and in these conditions during exploitation can occur large deformations at these that may cause a decrease in the exploitation safety of mining equipment. Research has followed in principal the analyze of deformations appear in metallic structures, and for realizing the researches has been used both a dimensional analysis and one that is based on the finite element method.Key words: metal structures, deformations, dimensional analysis, finite element methodINTRODUCTIONEvaluation and knowledge of deformations which appear in the metallic structures of the mining equip-ment is particularly important to assess their lifetime. Metallic construction used at mining equipment are welded metallic construction which must provide a ser-vice life as big as possible. [1]. A big problem of equipment is the welded metallic construction which over time has not been modernized but suffered only some repairs. The life of welded metal-lic construction of the mining equipment is very much influenced by the evolution of deformation suffered by them. Deformations suffered by metallic construction are caused by very high mechanical requests, but also be-cause phenomena of corrosion and dimensional change which appear by redistributing material, and they all ap-pear after a certain period of exploitation. Welded metal constructions have become increas-ingly popular in recent years, within the mining equip-ment, because of the advantages they have in compari-son with other structures obtained by other technologi-cal processes. Through its specificity, the process of achieving products in welded constructions presents a number of disadvantages arising primarily from work-ing with liquid materials [3].Welded metal constructions used in mining exploita-tion are very strong mechanically requested, but at the same time they are subject to the action of specific agents of working environment [4]. The life of these welded me-tallic construction is very much influenced by the evolu-tion of size and deformation suffered by them. Thus an important analysis which must be realized     relates to the evolution of the deformations that occur within the weld-ed metallic construction, and determining principal causes that cause these deformations [5].Construction steels for general use, type St 52.3, compared with carbon steels, have become widely used in construction machineries in the mining exploitation, due to the characteristics they have and allow a proper behavior of complex requests combined with action of corrosive working environment [6].Welded metal constructions used in the mining of coal are cyclic requested at fatigue, but also works in a chemically aggressive environment. The aggressive-ness of the environment in which the construction work can be explained by the presence in the atmosphere of large quantities of chemicals that can act as an aggres-sive environment [7]. Aggressive working environment is characterized mainly by the presence in the atmosphere of large quan-tities of sulfur from emissions from the local power plants. The apparition of corrosion within metallic structures cause a change in the size of the metal build-ing, and this influence the occurrence of phenomena by the type of deformations [8].Also it should be considered the fact that in the met-al construction of mining equipment is a random distri-bution of efforts and thus should be considered all the possibilities of requests that may arise.MATERIALSResearch has primarily aimed to determine the de-formations that occur in metallic structures made     of steel St 52.3, and to do research it must be used a di-mensional analysis, and an analysis using the finite ele-658   METALURGIJA 53 (2014) 4, 657-660G. PARASCHIV et al.: RESEARCH ON DEFORMATIONS WHICH APPEAR IN WITHIN THE METAL STRUCTURES...ment method. The research was focused on those weld-ed steel constructions that have been used a long time and through this analysis it was aimed to establish pos-sibilities which are for the safe use of such metallic con-structions. The use of this steel is indicated at the fabri-cation of resistance elements (beams, columns, sections, rails, brackets, etc.). Defects which appeared during operation are deter-mined by the incognizance of technological aspects , but also the use of materials with inadequate for pur-pose. Among the factors that have influence on the life of welded metal constructions are mentioned: the choice of materials and welding processes, chemical composi-tion, thermal influence zone, etc. To achieve desired re-sults in the research, it was initially determined the chemical composition for steel St 52.3 which is present-ed in Table 1.Table 1 The chemical composition of the steel St 52.3 / %C Mn Si  S  P  Al Ni Cr0,136 1,22 0,365 0,017 0,017 0,011 0,022 0,027For St 52.3 steel is recommended that up to a thick-ness of 10 / mm of pieces,they must not preheat, be-cause welding linear energy realize a sufficient preheat-ing for welding operation.Analyzed metallic construction “excavator arm ERc 1300” is obtained from the highlights of rolled St 52.3 steel with thickness of 10 / mm, positioned and assem-bled by manual welding with basic electrodes.RESULTS AND DISCUSSIONSTo realize the research was ralized initial a drawing of the excavator arm which is partially shown in Figure 1, and in this drawing were established primarily the dimensions component pieces and the arrangement and combination of them.Experimental research made at different time have shown that in the KL constructive element (Figure 1) of the excavator arm were occurred deformities increas-ingly larger, and this may cause deformation or break-age of the entire metal construction of excavator . These deformations can be determined by changing the mate-rial properties of the metal structure or appearance of intergranular corrosion phenomena and high mechani-cal requests. Thus in the first phase of experimental re-search it was visually analyzed the deformations area and were not found superficial corrosion areas where is currently a continuously coating layer Figure 2. Also, the method of deforming the excavator arm element is shown in Figure 3.Due to the lack of a visible surface corrosion in the next step we aimed to determine possible corrosion phenomena that may occur under the paint and can af-fect the metal structure. To identify these corrosion phe-nomena it was used in the experiments LAPTOSCOP Figure 1   Partial description of shape and dimensions of the excavator armFigure 2 The deformed element of the excavator armFigure 3   The mode of deformation of the excavator arm element659 METALURGIJA 53 (2014) 4, 657-660G. PARASCHIV et al.: RESEARCH ON DEFORMATIONS WHICH APPEAR IN WITHIN THE METAL STRUCTURES...type apparatus that allows non-destructive determina-tion of thickness of paint and oxides and thus can estab-lish the thickness of metal that is in that structure.The experiments were performed by making several measurements (18 measuring points) points along the metal piece KL, and the obatined results are presented in Table 2.Table 2   Thicknesses determined after measurements performed on the deformed element / mmNo. Thickness of the deformed elementThe thickness of the paint and oxidesMetallic mate-rial thickness1 10,96 0,967 9,9932 10,95 0,969 9,9813 10,92 0,967 9,9534 10,91 0,965 9,94551 0 , 9 0 1 , 0 0 1 9 , 8 9 961 0 , 9 1 1 , 1 0 8 9 , 8 0 271 0 , 8 9 1 , 1 4 7 9 , 7 4 381 0 , 9 2 1 , 1 6 7 9 , 7 5 391 0 , 9 1 1 , 2 8 3 9 , 6 2 710 10,93 1,288 9,64211 10,89 1,295 9,59512 10,96 1,152 9,80813 10,94 1,038 9,90214 10,93 0,984 9,94615 10,96 0,967 9,99316 10,96 0,961 9,99917 10,95 0,959 9,99118 10,94 0,952 9,988From the results shown in Table 2 it can be observed the fact that the thickness of the KL element is approxi-mately 10,9 / mm, and this size is formed from a layer of paint and oxide plus the thickness of the metal part. After the measurements was found that in the area of points 9 ÷ 11 is the thickest layers of paint and oxides, and in this area there is the smallest thickness of the metal layer , namely the thickness is reduced by 5-6 / % in relation to the new state. In these conditions it was observed that int his area the maximum deformation which extend and has an increasing length.To determine the causes of deformation of the KL structural element that have been considered and some of it blows received during the operation and that could produce a strain accidentally . It was also taken into ac-count this hypothesis given the shape deformation which occurred. Research has shown that the appear-ance of the deformation due to a hit is highly unlikely and in these conditions was switched to another method to confirm the results obtained in experimental research, namely the finite element method.Determining the deformation parameters by conven-tional analytical methods is not possible for massive spatial structures. Excavator arm ERc 1300, is a mas-sive spatial structure which can be studied using finite element method using a process of discretization, name-ly h-element method. Discretization was done with sec-ond order tetrahedral elements. These elements are used for good discretization with small errors on curved sur-faces. The third-order elements used at discretization of spline curves and surfaces generated in this way.To study it was used Autodesk Inventor 2011 program running on an Intel QuadCore 3.5 GHz computer. The ap-plication method of loads on the metal structure is shown in Figure 4, and the values     of loads after the three direc-tions OX, OY respectively OZ are shown in Table 3.Table 3 Operating conditions,  Force:1 / NLoad Type ForceVector X 0,000Vector Y -300 000,000Vector Z 0,000To apply the Finite Element Method it is necessary to be known in great detail the physical properties of the metal structure analyzed and a detailed presentation of them is presented in Table 4. Analyzing the physical properties of the metal structure analyzed is can be ob-served the fact that it has a very large load, and a fairly large area which demonstrates once again the complex character metal of the analyzed structure.Table 4   The physical properties of the metal structure analyzedMaterial DefaultMass 2 072,59 / kgArea 61 888 500 / mm2Volume 2 072 590 000 / mm3Center of Gravity x=14 783,613 / mm, y=1 523,341 / mmz=59,055 / mmAlso, Finite Element Analysis of steel structures is possible if physical and mechanical properties of the material which is made are known, and the analyzed case the material was steel St 52.3 with the properties shown in Table 5.Application of Finite Element Method for metallic structure analyzed is realized only after initially have been realized some advanced settings fot the applied fi-nite element and setting values     performed are presented in Table 6.Figure 4 The application of loads on steel structure660   METALURGIJA 53 (2014) 4, 657-660G. PARASCHIV et al.: RESEARCH ON DEFORMATIONS WHICH APPEAR IN WITHIN THE METAL STRUCTURES...Table 6 Advanced settingsAvg, Element Size (fraction of model diameter) 0,1Min, Element Size (fraction of avg, size) 0,2Grading Factor 1,5Applying the load on metal structure cause some re-actions of force type or the moment within constraints made    , and the values     obtained for them by applying the finite element method are presented in Table 7.Table 7 Reaction force and moment on constraintsMagnitude/ NComponent (X,Y,Z) / NMagni-tude / N·mComponent (X,Y,Z)/ N·mFixed Constraint:196 907,7294 011,112 106,493-15,88-23 515,5  -105,31186,792 0Fixed Constraint:2336 616-94 026 68,26733,69323 217  -59,370 0 Application of finite element method for the analy-sis of metal structure allowed obtaining both numerical values     for the deformations obtained on the element structure, Table 8, and highlighting the ways in which the deformation and its shape are produced is shown in Figure 5.Table 8 Result SummaryName Minimum MaximumVolume 2 072 590 000 / mm3Mass 16 290,5 / kgVon Mises Stress 0,091 / MPa 46,007 / MPa1st Principal Stress -1 010,573 / MPa 36,901 / MPa3rd Principal Stress -39,856 / MPa 7,041 / MPaDisplacement 0 / mm 2,963 / mmSafety Factor 4,499 / ul 15 / ulX Displacement -1,722 / mm 0 / mmY Displacement -2,422 / mm 2,46 / mmZ Displacement -0,263 / mm 0,011 / mmCONCLUSIONSFollowing experimental research and modeling car-ried out by finite element method we can draw the fol-lowing conclusions:-   welded construction of mining process equipment are strongly mechanically requested, but at the same time and are subjected to corrosion;-   metallic construction of mining equipment are com-plex structures whose modeling by finite element allows obtaining significant results;-   deposition of coatings of paint that has lower protec-tion features on metallic construction causes metal corrosion phenomena in depth metal structure;-   deformation structures are determined by mechani-cal actions, but they are enhanced by corrosion phe-nomena which cause a reduction in the thickness of metallic material;-   application of the finite element method allows high-lighting areas where are produced maximum defor-mations of structures, but also allows for confirma-tion of the results obtained in experimental research;-   deformations occur mainly in the case of those struc-tural elements that have horizontal position in the metal structure and in this regard it is recommended to adopt constructive changes, and adoption of heat and thermochemical treatments that increase resist-ance to deformation of them;-   adopting  appropriate  technological  solutions  can cause accidental occurrence of large deformations, and if one takes into account the complexity of the hardware and repair costs are very high.REFRENCES[1]   D. Dobrotă, Metalurgija, 53 (2014) 2, 179-182. [2]   C. Babis et al., Metalurgija, 53 (2014) 2, 251-253. [3]  L. Henning et al., EPA contract no, 68-Do-123, Midwest Research Institute, Kansas City, (1994).[4]   ANSI Z49.1, Section E5.4 pp. 12, American Welding So-ciety, 550 NW LeJeune Road, Miami, FL, 2005.[5]   Y, Wang et al., Materials Environ, Sci, Technol, 45 (2011) 15, 6539-6544.[6]   B. Chang et al., Journal of Materials Processing Technolo-gy 108 (2001) 3, 307-313.[6]   E. Bayraktar et al., Journal of Materials Processing Tech-nology 145 (2004) 1, 27-39.[7]   O. Chivu, Metalurgija, 52 (2013) 4, 465-468.[8]   D. Dobrotă, L. M. Cîrtînă, Proceedings of a Conference “Modern Technologies Quality and Restructuring – TMCR”, Chişinău, (2005) 2, 377-380.Note:   The responsible translator for English language is DELTRA CELES SRL, Bucharest, RomaniaTable 5 Physical and mechanical properties of steel St 52.3Name Steel, MildGeneral Mass Density 7,86 / g/cm3Yield Strength 207 / MPaUltimate Tensile Strength 345 / MPaStress Young’s Modulus 220 / GPaPoisson’s Ratio 0,275 / ulShear Modulus 86 274,5 / MPaFigure 5   The mode of deformation of the metal structure obtained by applying the finite element method

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