Author: Amarine Antonio

Shipbuilding and welding professional.
HULL, SHIP SURVEY, WELDING2 Comments

HULL SURVEY – WELDING STANDARD

Amarine Antonio

The welding joint’s configuration and their profile are playing a vital role in ship hull structure integrity. In this article I’d like to reveal some noted points which will be regularly observed during inspection. JOINT TOLERANCES AND REMEDIAL ACTIONS: 1-Butt joint: 2-Fillet joint 3-Lap joint 4-Special note: Fillet leg size for main longitudinal  The fillet weld is to be fully penetrated, otherwise fillet size is to be equivalent to the sectional area of the longitudinal members. General fillet size F1,F2 Frame of bulk carrier Bilge Keel & Pillar End Sheer strake and deck   Welding at high stress area For … Continue reading HULL SURVEY – WELDING STANDARD

HULL, SHIP SURVEY1 Comment

HULL SURVEY – GOOD BROUGHT IN

Amarine Antonio

In the most rule requirements,  the presence of the surveyor is required at times when materials or parts manufactured at places other than the shipyard are being installed aboard the ship concerned. The general conceptual flow of the acceptance inspection process is shown as below: Inspection Procedures Presentation of list Before the start of construction of the ship, a request should be made to the shipyard to submit a list of hull assembly units, equipment and materials which are brought-in or manufactured by a sub-contractor and intended to be used in the ship. These must be subjected to an acceptance … Continue reading HULL SURVEY – GOOD BROUGHT IN

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HULL SURVEY – BUILDING PROCEDURE

Amarine Antonio

There are two main types of building procedures. One is the frame erection system which was prevalent before 1950 and the other is the block assembling system adopted by almost all shipyards today. In this guidance, the building procedure employed is assumed to be the block assembling system. Frame erecting system This is an old practice adopted for wooden ships in many years ago and continuously adopted for iron and steel ships of riveted construction in the 19th Century. Even now, some small shipyards continue to use this method. Block assembling system During the World War II, the construction of … Continue reading HULL SURVEY – BUILDING PROCEDURE

HULL, SHIP SURVEY2 Comments

HULL SURVEY – GENERAL

Amarine Antonio

The purpose of this article series are guidance describing the general instructions for classification surveys during construction relating to hull construction and does not include those survey items concerning SOLAS Convention matters such as life saving, fire-fighting, etc. In general of view, i’m giving you the first glance for scopes of a surveyor: Responsibility for Quality Assurance “ The workmanship is to be of the best quality. During construction, the builder is to supervise and inspect in detail every job performed in shed (workshop) and yard (field) as well. ” This means that the first responsibility for quality assurance of … Continue reading HULL SURVEY – GENERAL

API 570 - PI, OIL & GAS1 Comment

Pressure Vessel RBI – intro

Amarine Antonio

RISK-BASED INSPECTION Risk-Based Inspection (RBI) ensures you are performing the right inspections (procedure), on the right assets, in the right areas, at the right frequency. With thousands of assets to monitor, it can be challenging to properly prioritize inspection investments in efforts to reduce loss of containment risks to acceptable levels. Whether dealing with pressure vessels, pressure relief devices, piping segments, pipelines, check valves, or pump casings, loss of containment risks should be identified and mitigated before they happen. Risk-Based Inspection (RBI) can help these risks be proactively mitigated. RBI is an approach used to assign risk to particular assets within … Continue reading Pressure Vessel RBI – intro

WELDING, WELDING METALLURGY2 Comments

TACK WELDER

Amarine Antonio

Tack welding is a major part of welding which are used as a temporary means to hold the components in the proper location, alignment, and distance apart, while welding. The engineers use high heat input process for the welding and the tack is applied by the shielded metal arc welding process. The tack is a very rapid quench application and a brittle, crack sensitive micro structure results usually at the root of the weld. There’re two type of tack-welds as defined in below attached file ( Temporary & Incorporated ) TACK WELDS For saving the qualification cost, some yard make … Continue reading TACK WELDER

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WELDING INTERRUPTION

Amarine Antonio

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

WELDING, Welding Engineer6 Comments

WELD PROXIMITY

Amarine Antonio

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