The Steel Catenary Riser(SCR)is a vital component for transporting oil and gas from the seabed to the floating platform.The harsh environmental conditions and complex platform motion make the SCR’s girth-weld prone t...The Steel Catenary Riser(SCR)is a vital component for transporting oil and gas from the seabed to the floating platform.The harsh environmental conditions and complex platform motion make the SCR’s girth-weld prone to fatigue failure.The structural stress fatigue theory and Master S-N curve method provide accurate predictions for the fatigue damage on the welded joints,which demonstrate significant potential and compatibility in multi-axial and random fatigue evaluation.Here,we propose a new frequency fatigue model subjected to welded joints of SCR under multiaxial stress,which fully integrates the mesh-insensitive structural stress and frequency domain random process and transforms the conventional welding fatigue technique of SCR into a spectrum analysis technique utilizing structural stress.Besides,a full-scale FE model of SCR with welds is established to obtain the modal structural stress of the girth weld and the frequency response function(FRF)of modal coordinate,and a biaxial fatigue evaluation about the girth weld of the SCR can be achieved by taking the effects of multi-load correlation and pipe-soil interaction into account.The research results indicate that the frequency-domain fatigue results are aligned with the time-domain results,meeting the fatigue evaluation requirements of the SCR.展开更多
围长较大的短码长准循环(QC)低密度奇偶校验(LDPC)码的显式构造对于QC-LDPC短码的理论研究与工程应用具有重要意义。首先提出一种基于成对策略的贪婪搜索算法,并根据此算法在列重J为4时的经验结果,归纳总结出一种具有双序列反序特征的...围长较大的短码长准循环(QC)低密度奇偶校验(LDPC)码的显式构造对于QC-LDPC短码的理论研究与工程应用具有重要意义。首先提出一种基于成对策略的贪婪搜索算法,并根据此算法在列重J为4时的经验结果,归纳总结出一种具有双序列反序特征的指数矩阵。随后证明了该指数矩阵对于任意行重L均对应于围长为8的QC-LDPC码。与现有的典型显式构造方法即最大公约数(GCD)方法相比,新QC-LDPC码提供的码长显著降低。最后,将指数矩阵的拆分拼接和掩膜处理技巧与新QC-LDPC码结合起来,设计出了译码性能在高信噪比区超过5G NR LDPC码的合成码。展开更多
An analysis of the girth weldability of Baosteel X80 UOE (U-ing-O-ing-Expanding) linepipes was conducted using manual shielded metal arc welding (SMAW) and semiautomatic self-shielded flux cored wire arc welding ...An analysis of the girth weldability of Baosteel X80 UOE (U-ing-O-ing-Expanding) linepipes was conducted using manual shielded metal arc welding (SMAW) and semiautomatic self-shielded flux cored wire arc welding (FCAW). A technical specification for the optimum quality of a girth welding joint was obtained through a large amount of testing. According to the requirements of America Petroleum Institute(API) standard 1104 and the standards of the 2nd West-East natural gas transmission pipeline project,the mechanical properties of a girth welding joint were estimated. In addition,the effect of the girth welding procedure specifications and the consumable' s suitability on the impact toughness of the girth welding joint was discussed.展开更多
A construction method based on the p-plane to design high-girth quasi-cyclic low-density parity-check (QC-LDPC) codes is proposed. Firstly the good points in every line of the p-plane can be ascertained through filt...A construction method based on the p-plane to design high-girth quasi-cyclic low-density parity-check (QC-LDPC) codes is proposed. Firstly the good points in every line of the p-plane can be ascertained through filtering the bad points, because the designed parity-check matrixes using these points have the short cycles in Tanner graph of codes. Then one of the best points from the residual good points of every line in the p-plane will be found, respectively. The optimal point is also singled out according to the bit error rate (BER) performance of the QC-LDPC codes at last. Explicit necessary and sufficient conditions for the QC-LDPC codes to have no short cycles are presented which are in favor of removing the bad points in the p-plane. Since preventing the short cycles also prevents the small stopping sets, the proposed construction method also leads to QC-LDPC codes with a higher stopping distance.展开更多
Based on the offshore standard DNV-OS-F101-2010,girth welding tests and girth weldability evaluations were carried out for the X65 and X70 UOE submarine pipelines of 3 wall thickness gauges,in which semi-automatic gas...Based on the offshore standard DNV-OS-F101-2010,girth welding tests and girth weldability evaluations were carried out for the X65 and X70 UOE submarine pipelines of 3 wall thickness gauges,in which semi-automatic gas metal arc welding (GMAW) was adopted matched with metal powder flux cored wire. The girth welding procedure specification (WPS) was optimized to obtain good quality and cold-crack-free girth weld joint without preheating and post-weld heat treatment. At the same time, porosities, inclusions and incomplete fusion defects were avoided. Girth weld joints were evaluated for tensile strength, bending, Vickers hardness, charpy impact toughness and crack tip opening displacement (CTOD) fracture toughness. Results show that all the girth weld joints have good mechanical performances,indicating that the irth weldabilitv of Baosteel' s UOE submarine pipelines is excellent in the case of semi-automatic GMAW.展开更多
Self-shielded flux-cored wire is a convenient and efficient consumable for pipeline field girth welding because of its self-protection characteristic and high deposition rate, especially for remote construction sites ...Self-shielded flux-cored wire is a convenient and efficient consumable for pipeline field girth welding because of its self-protection characteristic and high deposition rate, especially for remote construction sites in rugged terrain. From the perspective of pipeline safety, the impact toughness of the girth welds is an important factor in pipeline integrity ,which determines the crack arrest behavior in the girth welds. Therefore, improving the girth weld impact toughness is of primary importance in the field of pipeline girth welding. Three self-shielded flux-cored wires comprising different chemical composition systems have been applied to large diameter X80 UOE (U-ing-O- ing-Expanding) pipeline semi-automatic girth welding,and the impact toughness of the welds has been evaluated by girth weld chemical composition analysis and microstructural analysis using scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS) to investigate pipeline girth weld impact toughness and find ways to improve it. This helps in determining the main factors that influence girth weld impact toughness. Pipeline girth weld impact toughness is mainly determined by the final microstructure produced in the solid-state phase transition. In the as-weld state,acicular ferrite (AF) and fine bainite (FB) are a benefit to the impact toughness. For multilayer semiautomatic self-shielded flux-cored wire welding, the normalizing and tempering function of the latter beads to the initial beads plays an important role in the transition of girth weld microstructure, which affects the impact toughness. The original AF and FB and the corresponding heat treatment microstructure of the fine and uniform block ferrite and pearlite result in very good impact toughness. The following two mechanisms are found to promote the production of AF and FB in the girth weld. First, elements promoting the broadening of the austenitic region, such as Ni, C, Cu, and Mn, induce low temperature phase transitions and restrain the opposing function of Al, which is a benefit to the production of AF and FB. Second, dispersed high-melting-point inclusions, especially Al2O3 ,induce the nucleated production of AF. The advantageous function of inclusions is determined by their shape, distribution, and dimension. Dispersed spherical inclusions of small dimension are a benefit to the production of AF, and result in good impact toughness.展开更多
Aim: To report our experience with penile girth augmentation using liquid injectable silicone. Methods: Between August 2003 and July 2006, 324 men (mean age 35 years, range 19-65 years) received a series of liquid...Aim: To report our experience with penile girth augmentation using liquid injectable silicone. Methods: Between August 2003 and July 2006, 324 men (mean age 35 years, range 19-65 years) received a series of liquid silicone subcutaneous injections between the penile skin and the corpora cavernosa on the dorsal and lateral aspects of the penile shaft, under local anesthesia. Digital photographs taken pre- and post-procedure (n = 324), and penile contour measurements (n = 30) yielded objective results. Subjective results were derived from patient and partner testimony of satisfaction. Follow-up averaged 20 months (range 1-36 months). Results: Three hundred and twenty-four procedures were primary augmentations. Most men (61%) were married, 7% were accompanied by their partners, and 93% were circumcised. The mean measured penile circumference was 9.5 cm (7.5-11.5 cm) pretreatment and 12.1 cm (10.3-15.3 cm) post-treatment (mean increase of 27% in circumference and 0.84 cm in diameter). Patient and partner satisfaction was already expressed after the first two treatments. Sexual activity could be resumed after 8 h. Complications (mild bruising) were easily resolved. Conclusion: Penile girth augmentation using liquid injectable silicone yields very satisfactory short-term results with no immediate or short-term complications.展开更多
The existing constructions of quasi-cyclic low-density parity-check (QC-LDPC) codes do not consider the problems of small stopping sets and small girth together in the Tanner graph, while their existences will lead ...The existing constructions of quasi-cyclic low-density parity-check (QC-LDPC) codes do not consider the problems of small stopping sets and small girth together in the Tanner graph, while their existences will lead to the bit error rate (BER) performance of QC-LDPC codes being much poorer than that of randomly constructed LDPC codes even decoding failure. To solve the problem, some theorems of the specific chosen parity-check matrix of QC-LDPC codes without small stopping sets and small girth are proposed. A novel construction for QC-LDPC codes with long block lengths is presented by multiplying mmin or the multiple of mmin, which is the minimum order of the identity matrix for the chosen parity-check matrix. The simulation results show that the specific chosen parity-check matrix of QC-LDPC codes can effectively avoid specified stopping sets and small girth and exhibit excellent BER performance than random LDPC codes with the same longer codes length.展开更多
This paper presents a novel regular Quasi-Cyclic (QC)Low Density Parity Check (LDPC)codes with columnweight three and girth at least eight.These are designed on the basis of combinatorial design in which subsets appli...This paper presents a novel regular Quasi-Cyclic (QC)Low Density Parity Check (LDPC)codes with columnweight three and girth at least eight.These are designed on the basis of combinatorial design in which subsets applied for the construction of circulant matrices are determined by a particular subset.Considering the nonexistence of cycles four and six in the structure of the parity check matrix,a bound for their minimum weight is proposed.The simtdations conducted confirm that without applying a masking technique,the newly implemented codes have a performance similar to or better than other well-known codes.This is evident in the waterfall region, while their error floor at very low Bit Error Rate (BER)is expected.展开更多
Based on API STD 1104-2005 and CSA Z662-2007, field girth welding tests and girth weldability evaluations were executed for three types of wall thickness X70 UOE pipeline, in which the most popular main line girth wel...Based on API STD 1104-2005 and CSA Z662-2007, field girth welding tests and girth weldability evaluations were executed for three types of wall thickness X70 UOE pipeline, in which the most popular main line girth welding method, single-wire automatic gas metal arc welding (GMAW), was used. The welding procedure specification was optimized to achieve a good quality and cold-crack-free girth weld joint without preheating or post-weld heat treatment. In addition ,porosities ,inclusions ,and incomplete fusion defects were avoided. The tensile strength,bending ,Vickers hardness,Charpy V-notch impact toughness, and crack tip opening displacement fracture toughness of the girth weld joint were evaluated, and the field girth weldability of Baosteel' s X70 UOE pipeline is joint exhibited good mechanical performance. Thus, the excellent for automatic GMAW.展开更多
According to the requirements of welding process for vortex type compressor of air conditioner manufactured in product line, a special girth welding machine with PLC as control core was developed, which had both uprig...According to the requirements of welding process for vortex type compressor of air conditioner manufactured in product line, a special girth welding machine with PLC as control core was developed, which had both upright and 45 ° incline service positions. And some key technologies were researched, such as structural design of machine body, reliable conduction of rotary weldments and quality control of welding process and so on. The experimental results showed that this machine could satisfy the requirements of welding quality and girth welding technology, results also proved the machine was a high-effwiency and low-cost automatic welding device.展开更多
The girth plays an important role in the design of LDPC codes. In order to determine the girth of Tanner(5,7) quasi-cyclic( QC) LDPC codes with length 7p for p being a prime with the form 35 m + 1,the cycles of length...The girth plays an important role in the design of LDPC codes. In order to determine the girth of Tanner(5,7) quasi-cyclic( QC) LDPC codes with length 7p for p being a prime with the form 35 m + 1,the cycles of lengths 4,6,8,and 10 are analyzed. Then these cycles are classified into sixteen categories,each of which can be expressed as an ordered block sequence,or a certain type. It is also shown that the existence of these cycles is equal to polynomial equations over Fpwho has a 35th unit root. We check if these polynomial equations have a 35th unit root and obtain the girth values of Tanner(5,7) QC LDPC codes.展开更多
A graph G is said to be an (l,d)-graph (with respect to edges) if d(G-E)≤d,E E(G) such that | E |≤l-1.The l-diameter-stable graphs are (l,d)-graphs with diameter d.In this paper some new results on diame...A graph G is said to be an (l,d)-graph (with respect to edges) if d(G-E)≤d,E E(G) such that | E |≤l-1.The l-diameter-stable graphs are (l,d)-graphs with diameter d.In this paper some new results on diameter-stable graphs are obtained.展开更多
According to the requirements of Queensland Gas Company Ltd. (QGC), the operator of the Queensland Curtis LNG (QCLNG) pipeline project in Australia, girth welding experiments and weldability evaluations have been ...According to the requirements of Queensland Gas Company Ltd. (QGC), the operator of the Queensland Curtis LNG (QCLNG) pipeline project in Australia, girth welding experiments and weldability evaluations have been carded out for three X70 UOE pipes from Baosteel based on API 1104 standards. Shielded metal arc welding (SMAW) and gas- shielded flux-cored wire arc welding (FCAW-G) have been applied, and the girth weld joint quality and mechanical performance were evaluated. It was found that the field girth weldability of Baosteel' s XT0 UOE pipes was excellent under the conditions used here and satisfied the requirements of the QCLNG project for field girth welding construction. Furthermore,Baosteel has offered a solution to the QCLNG project for pipeline girth welding in which the girth welding joint design, selection of welding processes and consumables, welding procedures, techniques and joint inspections are included. Such research provides important guidance for the difficult tie-in welding applications for the construction of the QCLNG pipelines in the field.展开更多
基金financially supported by the Director Fund of National Energy Deepwater Oil and Gas Engineering Technology Research and Development Center(Grant No.KJQZ-2024-2103)。
文摘The Steel Catenary Riser(SCR)is a vital component for transporting oil and gas from the seabed to the floating platform.The harsh environmental conditions and complex platform motion make the SCR’s girth-weld prone to fatigue failure.The structural stress fatigue theory and Master S-N curve method provide accurate predictions for the fatigue damage on the welded joints,which demonstrate significant potential and compatibility in multi-axial and random fatigue evaluation.Here,we propose a new frequency fatigue model subjected to welded joints of SCR under multiaxial stress,which fully integrates the mesh-insensitive structural stress and frequency domain random process and transforms the conventional welding fatigue technique of SCR into a spectrum analysis technique utilizing structural stress.Besides,a full-scale FE model of SCR with welds is established to obtain the modal structural stress of the girth weld and the frequency response function(FRF)of modal coordinate,and a biaxial fatigue evaluation about the girth weld of the SCR can be achieved by taking the effects of multi-load correlation and pipe-soil interaction into account.The research results indicate that the frequency-domain fatigue results are aligned with the time-domain results,meeting the fatigue evaluation requirements of the SCR.
文摘围长较大的短码长准循环(QC)低密度奇偶校验(LDPC)码的显式构造对于QC-LDPC短码的理论研究与工程应用具有重要意义。首先提出一种基于成对策略的贪婪搜索算法,并根据此算法在列重J为4时的经验结果,归纳总结出一种具有双序列反序特征的指数矩阵。随后证明了该指数矩阵对于任意行重L均对应于围长为8的QC-LDPC码。与现有的典型显式构造方法即最大公约数(GCD)方法相比,新QC-LDPC码提供的码长显著降低。最后,将指数矩阵的拆分拼接和掩膜处理技巧与新QC-LDPC码结合起来,设计出了译码性能在高信噪比区超过5G NR LDPC码的合成码。
文摘An analysis of the girth weldability of Baosteel X80 UOE (U-ing-O-ing-Expanding) linepipes was conducted using manual shielded metal arc welding (SMAW) and semiautomatic self-shielded flux cored wire arc welding (FCAW). A technical specification for the optimum quality of a girth welding joint was obtained through a large amount of testing. According to the requirements of America Petroleum Institute(API) standard 1104 and the standards of the 2nd West-East natural gas transmission pipeline project,the mechanical properties of a girth welding joint were estimated. In addition,the effect of the girth welding procedure specifications and the consumable' s suitability on the impact toughness of the girth welding joint was discussed.
基金supported by the National Natural Science Foundation of China (60572093)Specialized Research Fund for the Doctoral Program of Higher Education (20050004016)
文摘A construction method based on the p-plane to design high-girth quasi-cyclic low-density parity-check (QC-LDPC) codes is proposed. Firstly the good points in every line of the p-plane can be ascertained through filtering the bad points, because the designed parity-check matrixes using these points have the short cycles in Tanner graph of codes. Then one of the best points from the residual good points of every line in the p-plane will be found, respectively. The optimal point is also singled out according to the bit error rate (BER) performance of the QC-LDPC codes at last. Explicit necessary and sufficient conditions for the QC-LDPC codes to have no short cycles are presented which are in favor of removing the bad points in the p-plane. Since preventing the short cycles also prevents the small stopping sets, the proposed construction method also leads to QC-LDPC codes with a higher stopping distance.
文摘Based on the offshore standard DNV-OS-F101-2010,girth welding tests and girth weldability evaluations were carried out for the X65 and X70 UOE submarine pipelines of 3 wall thickness gauges,in which semi-automatic gas metal arc welding (GMAW) was adopted matched with metal powder flux cored wire. The girth welding procedure specification (WPS) was optimized to obtain good quality and cold-crack-free girth weld joint without preheating and post-weld heat treatment. At the same time, porosities, inclusions and incomplete fusion defects were avoided. Girth weld joints were evaluated for tensile strength, bending, Vickers hardness, charpy impact toughness and crack tip opening displacement (CTOD) fracture toughness. Results show that all the girth weld joints have good mechanical performances,indicating that the irth weldabilitv of Baosteel' s UOE submarine pipelines is excellent in the case of semi-automatic GMAW.
文摘Self-shielded flux-cored wire is a convenient and efficient consumable for pipeline field girth welding because of its self-protection characteristic and high deposition rate, especially for remote construction sites in rugged terrain. From the perspective of pipeline safety, the impact toughness of the girth welds is an important factor in pipeline integrity ,which determines the crack arrest behavior in the girth welds. Therefore, improving the girth weld impact toughness is of primary importance in the field of pipeline girth welding. Three self-shielded flux-cored wires comprising different chemical composition systems have been applied to large diameter X80 UOE (U-ing-O- ing-Expanding) pipeline semi-automatic girth welding,and the impact toughness of the welds has been evaluated by girth weld chemical composition analysis and microstructural analysis using scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS) to investigate pipeline girth weld impact toughness and find ways to improve it. This helps in determining the main factors that influence girth weld impact toughness. Pipeline girth weld impact toughness is mainly determined by the final microstructure produced in the solid-state phase transition. In the as-weld state,acicular ferrite (AF) and fine bainite (FB) are a benefit to the impact toughness. For multilayer semiautomatic self-shielded flux-cored wire welding, the normalizing and tempering function of the latter beads to the initial beads plays an important role in the transition of girth weld microstructure, which affects the impact toughness. The original AF and FB and the corresponding heat treatment microstructure of the fine and uniform block ferrite and pearlite result in very good impact toughness. The following two mechanisms are found to promote the production of AF and FB in the girth weld. First, elements promoting the broadening of the austenitic region, such as Ni, C, Cu, and Mn, induce low temperature phase transitions and restrain the opposing function of Al, which is a benefit to the production of AF and FB. Second, dispersed high-melting-point inclusions, especially Al2O3 ,induce the nucleated production of AF. The advantageous function of inclusions is determined by their shape, distribution, and dimension. Dispersed spherical inclusions of small dimension are a benefit to the production of AF, and result in good impact toughness.
文摘Aim: To report our experience with penile girth augmentation using liquid injectable silicone. Methods: Between August 2003 and July 2006, 324 men (mean age 35 years, range 19-65 years) received a series of liquid silicone subcutaneous injections between the penile skin and the corpora cavernosa on the dorsal and lateral aspects of the penile shaft, under local anesthesia. Digital photographs taken pre- and post-procedure (n = 324), and penile contour measurements (n = 30) yielded objective results. Subjective results were derived from patient and partner testimony of satisfaction. Follow-up averaged 20 months (range 1-36 months). Results: Three hundred and twenty-four procedures were primary augmentations. Most men (61%) were married, 7% were accompanied by their partners, and 93% were circumcised. The mean measured penile circumference was 9.5 cm (7.5-11.5 cm) pretreatment and 12.1 cm (10.3-15.3 cm) post-treatment (mean increase of 27% in circumference and 0.84 cm in diameter). Patient and partner satisfaction was already expressed after the first two treatments. Sexual activity could be resumed after 8 h. Complications (mild bruising) were easily resolved. Conclusion: Penile girth augmentation using liquid injectable silicone yields very satisfactory short-term results with no immediate or short-term complications.
基金supported by the National Natural Science Foundation of China (60572093)Specialized Research Fund for the Doctoral Program of Higher Education (20050004016)
文摘The existing constructions of quasi-cyclic low-density parity-check (QC-LDPC) codes do not consider the problems of small stopping sets and small girth together in the Tanner graph, while their existences will lead to the bit error rate (BER) performance of QC-LDPC codes being much poorer than that of randomly constructed LDPC codes even decoding failure. To solve the problem, some theorems of the specific chosen parity-check matrix of QC-LDPC codes without small stopping sets and small girth are proposed. A novel construction for QC-LDPC codes with long block lengths is presented by multiplying mmin or the multiple of mmin, which is the minimum order of the identity matrix for the chosen parity-check matrix. The simulation results show that the specific chosen parity-check matrix of QC-LDPC codes can effectively avoid specified stopping sets and small girth and exhibit excellent BER performance than random LDPC codes with the same longer codes length.
文摘This paper presents a novel regular Quasi-Cyclic (QC)Low Density Parity Check (LDPC)codes with columnweight three and girth at least eight.These are designed on the basis of combinatorial design in which subsets applied for the construction of circulant matrices are determined by a particular subset.Considering the nonexistence of cycles four and six in the structure of the parity check matrix,a bound for their minimum weight is proposed.The simtdations conducted confirm that without applying a masking technique,the newly implemented codes have a performance similar to or better than other well-known codes.This is evident in the waterfall region, while their error floor at very low Bit Error Rate (BER)is expected.
文摘Based on API STD 1104-2005 and CSA Z662-2007, field girth welding tests and girth weldability evaluations were executed for three types of wall thickness X70 UOE pipeline, in which the most popular main line girth welding method, single-wire automatic gas metal arc welding (GMAW), was used. The welding procedure specification was optimized to achieve a good quality and cold-crack-free girth weld joint without preheating or post-weld heat treatment. In addition ,porosities ,inclusions ,and incomplete fusion defects were avoided. The tensile strength,bending ,Vickers hardness,Charpy V-notch impact toughness, and crack tip opening displacement fracture toughness of the girth weld joint were evaluated, and the field girth weldability of Baosteel' s X70 UOE pipeline is joint exhibited good mechanical performance. Thus, the excellent for automatic GMAW.
文摘According to the requirements of welding process for vortex type compressor of air conditioner manufactured in product line, a special girth welding machine with PLC as control core was developed, which had both upright and 45 ° incline service positions. And some key technologies were researched, such as structural design of machine body, reliable conduction of rotary weldments and quality control of welding process and so on. The experimental results showed that this machine could satisfy the requirements of welding quality and girth welding technology, results also proved the machine was a high-effwiency and low-cost automatic welding device.
基金Sponsored by the National Natural Science Foundation of China(Grant Nos.61372074 and 91438101)the National High Technology Research and Development Program of China(Grant No.2015AA01A709)
文摘The girth plays an important role in the design of LDPC codes. In order to determine the girth of Tanner(5,7) quasi-cyclic( QC) LDPC codes with length 7p for p being a prime with the form 35 m + 1,the cycles of lengths 4,6,8,and 10 are analyzed. Then these cycles are classified into sixteen categories,each of which can be expressed as an ordered block sequence,or a certain type. It is also shown that the existence of these cycles is equal to polynomial equations over Fpwho has a 35th unit root. We check if these polynomial equations have a 35th unit root and obtain the girth values of Tanner(5,7) QC LDPC codes.
基金Project supported by the Shanghai Leading Academic Discipline Project (Grant No. J50101)
文摘A graph G is said to be an (l,d)-graph (with respect to edges) if d(G-E)≤d,E E(G) such that | E |≤l-1.The l-diameter-stable graphs are (l,d)-graphs with diameter d.In this paper some new results on diameter-stable graphs are obtained.
文摘According to the requirements of Queensland Gas Company Ltd. (QGC), the operator of the Queensland Curtis LNG (QCLNG) pipeline project in Australia, girth welding experiments and weldability evaluations have been carded out for three X70 UOE pipes from Baosteel based on API 1104 standards. Shielded metal arc welding (SMAW) and gas- shielded flux-cored wire arc welding (FCAW-G) have been applied, and the girth weld joint quality and mechanical performance were evaluated. It was found that the field girth weldability of Baosteel' s XT0 UOE pipes was excellent under the conditions used here and satisfied the requirements of the QCLNG project for field girth welding construction. Furthermore,Baosteel has offered a solution to the QCLNG project for pipeline girth welding in which the girth welding joint design, selection of welding processes and consumables, welding procedures, techniques and joint inspections are included. Such research provides important guidance for the difficult tie-in welding applications for the construction of the QCLNG pipelines in the field.