WELDING INTERRUPTION

Definition – Interruption of welding means dropping from preheat temperature to ambient temperature prior to completion of welding or performing PWHT. This aspects most applied on high heat-sensitive material like (P3, P4, P5A, P5C, 10H High alloy materials) with regarding to Cold cracking or HIC. The weld can be interrupted and the weld may be allowed to cool prior to post weld heat treatment, provided the following conditions are satisfied: 1. A minimum of 3/8 in. thickness of weld is deposited or 25% of the welding groove is filled, whichever is greater 2. The weld is allowed to cool slowly … Continue reading WELDING INTERRUPTION

WELD PROXIMITY

Purpose of Welding proximity requirement is: 1 – To avoid the overlapping HAZ, the lowering of the welding HAZ mechanical properties which is not covered in WPS is approved for welding configuration.  2- To avoid the duplicate of residual stress between two joints which may combine with the load during service, this leads to structural failure due to the total combined local stress exceeding allowable stress. Weld proximity is covered by a number of international standards. Extracts from these standards are shown below and summarized in the following table: Standard Applies to The minimum distance between weld toes Notes BS … Continue reading WELD PROXIMITY

FCAW Welder may be qualified by volumetric NDE?

During reading between code D1.1 & ASME IX, a confusion point about welder qualification testing method RT/UT can be carried out in spite of Bend test. Note: From Asme IX extract, there’s no mention about the RT test can be used as alternatives for welder qualification in FCAW process. But as per the Interpretation, it can be used. ENJOY! Note that: If the welding with unlist material, the procedure of Welder qualification to be follow as required in table 452.1 (a) Continue reading FCAW Welder may be qualified by volumetric NDE?

GTAW CS TO SS SOLUTION

NOTE: APPLYING ONLY ON ASME IX GTAW PIPING WELDING Some contractors use the essential variable tables (QW-352 thru 357) to minimize their costs. For instance, they might test the welder for stainless steel material by using carbon steel material. Consider the actual project material is stainless steel and you do not want to waste stainless steel material for testing. You ask the welder to weld in carbon steel material but with stainless steel filler metal. Based on the essential variable table P number 1 (Carbon Steel) qualifies P 8 (Stainless Steel), and the F number is the same. So you … Continue reading GTAW CS TO SS SOLUTION

WELDING POSITION AND WPQR VARIABLES

The most common control points for welder performance are: Welding position Base metal F-No of Electrode/Filler Backing inert condition Pre-Heating prior to next weld (special interval between shifts) Electrode storage condition The qualified thickness Refer to the ASME IX & D1.1 extract as below: D1.1 WELDER PERFORMANCE POSITION AND VARIABLES IX WELDER PERFORMANCE POSITION AND VARIABLES Key Note on Down-hill welding: Normally, the Downhill welding should be avoided in design to prevent any mis-observed defects and make it sound welding practices on-board. Following the Code requirement, the changes in welding position is extracted as below: ASME IX : Down-hill welding … Continue reading WELDING POSITION AND WPQR VARIABLES

DT & NDT specifying for PQR

WPS/PQR Qualification The WPS for both the main welding procedures and weld repair procedures an oil and gas project shall be submitted by CONTRACTOR to Client / COMPANY normally one month minimum before the point of qualification tests. The WPS shall be accompanied by a summary table showing: process, consumables, direction of welding, type of weld, WPS no., test weld wall thickness and scope of qualification. The welding procedure qualification tests shall not be undertaken until the COMPANY Inspector (COMPANY’S authorized representatives or members) has given his approval of the principle on the said WPS. CONTRACTOR shall demonstrate by qualification … Continue reading DT & NDT specifying for PQR

From PQR to WPS – Introduction

Here is the shortcut to understand the step by step that how to make a WPS with the initial information supplied from contract specification. DEFINITION Welding Procedure Specification (WPS) : A WPS is a written qualified welding procedure prepared to provide direction for making production welds to code requirements. Procedure Qualification Record (PQR) : A PQR is a record of the welding data used to weld a test coupon. Test Coupon : A weld or Braze assembly for procedure or performance qualification testing. The coupon may be any product from plate, Pipe, tube, etc., and may be a fillet weld, … Continue reading From PQR to WPS – Introduction

New Shipbuilding Knowledge from Design to Construction

For first sight on Shipbuilding engineering knowledge, it’ll be more easy to understand what/how the ship be built in a yard from design to delivery by overview one typical Shipyard’s organization: SHIPBUILDING ENGINEERING ORGANIZATION Hereby the Essential knowledge points list … Continue reading New Shipbuilding Knowledge from Design to Construction