Pengendalian Kualitas Pengelasan Pada Proyek Pipeline Sabar#2

PT. ICG is a company that handles the pipeline welding process at PetroChina Jabung Ltd. The welding process carried out is cutting, rolling, pressing and painting. The problem that occurs is that 243 defects are found from the output of 457 welding points. The types of defects after the welding process included 106 points of Root Cancellation defects, 99 points of Incomplete fusion, 29 points of Porosity, 8 points of Slug Inclusion, and 1 point of Tungsten Inclusion. This study aims to control quality by looking at the sigma value of the pipeline production process and analyzing the improvements that should be made to reduce the defects that occur. The results of the calculation of Defect Per Million Opportunities (DPMO) show that the number of welding defects that arise every one million opportunities is 174,10. The quality of the welding process in the pipeline Sabar # 2 project is at a sigma value of 2,43 with a DPMO value of 174,10. From the results of the sigma value obtained, this value is still far from the expectations of Petrochina's management to achieve a minimum sigma value of 4,0. The potential causes of weld defects include welding machines, work errors, work methods and work environment.

Discussion on the Quality Control Measures of Automatic Welding in Southern Mountain Pipeline

The gas pipeline project of Guangxi Liquefied Natural Gas (LNG) project is the first automatic welding project in southern China. The welding quality is an important indicator to directly determines the construction quality of local pipeline welding, and also an important part of improving work efficiency. The implementation of the new process can bring great convenience to the work, improve the mechanical work efficiency, and achieve intelligent realization, not only saves the cost, but also standardize the automatic welding pipeline welding quality.

Effect of tempered bead techniques on maximum HAZ hardness for in service pipeline welding

This research intends to investigate the main factors of tempered bead techniques affecting on maximum HAZ hardness for in-service pipeline welding. Tempering parameters to be considered are the overlap ratio, weld bead sequences, and subsequent welding processes. This research consists of two parts of experimental procedure. Firstly, critical HAZ hardness (< 350 HV) in the first weld bead was estimated using computational simulation. Secondly, welding experiments were conducted with tempered techniques. Experimental setup included the used material of API 5L Gr. B pipe steel with nominal size of DN 200, wall thickness of 8.18 mm, and water piping How of 18.77 m3/hr. As a results, it suggested that the overlap weld ratio of 50h and 75%, weld bead sequences, as well as subsequent SMAW processes, were proficient of reducing significantly maximum HAZ hardness at the weld root. Nevertheless, in the case that the weld root was built up, maximum HAZ hardness was slightly changed with different weld bead sequences.

Mechanical Properties of Micro-Zones of X80 Pipeline Welding Joints

Due to the inhomogeneous mechanical properties of laser welding joints, it is necessary that the local mechanical properties of welding joints are measured for the assessment of the whole welding joints. Especially for mechanical properties test in heat affected zone of welding joints. Two methods of micro shear test and hardness test to measure mechanical properties of micro-zones were introduced. Using these two methods the mechanical properties of the micro-zones of X80 pipeline welding joint are determined and compared. The results showed that the micro shear test could be intuitively, quantitatively and continuously describe the strength and plasticity of the regional heterogeneity distribution, suitable for the assessment of the mechanical properties and fracture toughness of welding joints.

Research on the Mechanical Performance and Crack Defects Assessment of X65 Marine Pipeline Welding Joint

In order to study the influence of different types of weld defects, such as slag inclusion, porosity, incomplete fusion, incomplete fusion, burn through, crack on the mechanical performance of X65 marine pipe welding joint (Φ323.9 x 16 mm), the test on the mechanical properties of static tensile, fracture toughness CTOD and fatigue life were carried out to achieve the maximal defect tolerance size allowed in this paper. Research shows that the existence of crack defects would significantly reduce the fracture strength and the fatigue life of welded joint, the application of the maximal defect tolerance size allowed based on crack defects assessment can provide referential basis for the safe and stable operation of marine pipelines.

Development of an Effective ASME IX Welding Procedure Qualification Program for Pipeline Facility and Fabrication Welding

For cross country pipeline welding in Canada, welding procedures shall be qualified in accordance with the requirements of CSA Z662 Oil and Gas Pipeline Systems. For pipeline facility and fabrication welding on systems designed in accordance with CSA Z662 or ASME B31.4, welding procedures qualified in accordance with the requirements of ASME Boiler & Pressure Vessel Code Section IX are permitted and generally preferred. Welding procedures qualified in accordance with ASME IX provide advantages for pipeline facility and fabrication applications as a result of the flexibility achieved through the larger essential variable ranges. The resulting welding procedures have broader coverage on material thickness, diameter, joint configuration and welding positions. Similarly, ASME IX is more flexible on welder performance qualification requirements and accordingly a welder will have wider range of performance qualifications. When applied correctly, the use of ASME IX welding procedures often means significantly fewer welding procedures and welder performance qualifications are required for a given scope of work. Even though ASME IX qualified welding procedures have been widely used in pipeline facility and fabrication welding, it is not well understood on how to qualify the welding procedures in accordance with ASME IX and meet the additional requirements of the governing code or standard such as CSA Z662 in Canada. One significant consideration is that ASME IX refers to the construction code for the applicability of notch toughness requirements for welding procedure qualification, yet CSA Z662 and ASME B31.4 are both silent on notch toughness requirements for welding procedure qualification. This paper explains one preferred method to establish and develop an effective ASME IX welding procedure qualification program for pipeline facility and fabrication welding while ensuring suitability for use and appropriate notch toughness requirements. The paper discusses topics such as base material selection, welding process, welding consumable consideration and weld test acceptance criteria.