Author: Amarine Antonio

Shipbuilding and welding professional.
WELDING, Welding EngineerLeave a comment

Change electrode manufacture, vendor in welding WPS.

Amarine Antonio

If welding is to be performed according to a welding procedure specification, it is possible that changing the electrode manufacturer will invalidate the approval of the procedure to the code/standard on which it was based. The manufacturer or ‘trade name’ of the electrode can be classed as an essential variable in a given weld procedure. The extent to which re-qualification is necessary will vary from code to code. For example, in EN ISO 15614-1[1] and in the UK standard BS 4515:2004[2], approval is only restricted to the specific make of electrode if impact testing is required as part of the procedure qualification. On the … Continue reading Change electrode manufacture, vendor in welding WPS.

Mechanical, OIL & GASLeave a comment

Portable hardness test tools

Amarine Antonio

There are several portable hardness testers available, with some more appropriate to certain situations than others. The particular hardness tester for the job would depend on what you needed to find out and why. For example, a Barcol hardness tester for use on Al alloys is generally used as a comparative tool; to indicate a loss in strength in damaged regions of a structure compared with undamaged regions or virgin material. Barcol hardness testers are very portable and are good for this type of comparative work, but the conversion to more widely recognized hardness scales is only approximate. Telebrineller testers. … Continue reading Portable hardness test tools

BUILDING, WELDINGLeave a comment

Plastic (PPE, HDPE) welding standards

Amarine Antonio

There are tests for plastic welds, below is a selection of relevant tests. EN 12814-1:1999: ‘Testing of welded joints of thermoplastics semi-finished products – Part 1: Bend test’ EN 12814-2:2000: ‘Testing of welded joints of thermoplastics semi-finished products – Part 2: Tensile test’ EN 12814-3:2000: ‘Testing of welded joints of thermoplastics semi-finished products – Part 3: Tensile creep test’ EN 12814-4:2001: ‘Testing of welded joints of thermoplastics semi-finished products – Part 4: Peel test’ EN 12814-5:2000: ‘Testing of welded joints of thermoplastics semi-finished products – Part 5: Macroscopic examination’ EN 12814-6:2000: ‘Testing of welded joints of thermoplastics semi-finished products – … Continue reading Plastic (PPE, HDPE) welding standards

WELDING, WELDING METALLURGYLeave a comment

Weld proximity, between two seams standard

Amarine Antonio

Weld proximity is covered by a number of international standards. Extracts from these standards are shown below and summarised in the following table: Standard Applies to Minimum distance between weld toes Notes BS 2633:1987 Ferritic steel pipework 4t t= nominal thickness of the pipe See below for notes on attachment welds. BS 4515:2009 C-Mn pipelines 4t t= pipe thickness BS 2971:1991 Carbon steel pipework Agreed by parties – PD 5500:2012 Pressure vessels 4e or 100mm whichever is greater e= design thickness Refers to the staggering of longitudinal welds ASME B&PV Boilers and pressure vessels Not specified – BS 2633 ‘Class I … Continue reading Weld proximity, between two seams standard

WELDING, WELDING METALLURGYLeave a comment

Time delay before applying NDT in welding

Amarine Antonio

The following standards stipulate delay time before inspection: BS EN 1011-2:2001 Welding – Recommendations for welding of metallic materials – Part 2: Arc welding of ferritic steels (with amendment AMD 14926 Feb 2004) Paragraph 18 states: ‘Due to the risk of delayed cracking, a period of at least 16 hours is generally required before the final inspection is made of as-welded fabrications. The minimum time may be reduced for thin materials below 500N/mm2 yield strength or increased for materials of a thickness greater than 50mm or of yield strength over 500 N/mm2 … Welds that have been heat-treated to reduce hydrogen content … Continue reading Time delay before applying NDT in welding

Metallurgy, WELDING METALLURGYLeave a comment

Austenite Stainless Steel at high-temperature (embrittlement)

Amarine Antonio

The phenomenon of embrittlement in austenitic stainless steel welds exposed to high temperature is accelerated by the presence of delta ferrite. To avoid solidification cracking in austenitic stainless steel welds, the composition of the filler material must be optimized to ensure that there is some delta ferrite present in the weld metal (typically >3%). However, delta ferrite transforms into intermetallic phases, notably the sigma phase, faster than austenite either during high-temperature service or during post-weld heat treatment (PWHT). Sigma phase is an intermetallic with an approximate chemical formula FeCr and, as with most intermetallics, it is very brittle and hence … Continue reading Austenite Stainless Steel at high-temperature (embrittlement)

Metallurgy, WELDING METALLURGY1 Comment

Duplex piping and seawater

Amarine Antonio

22%Cr duplex stainless steels are not suitable for elevated temperature unprotected seawater applications because they suffer from the crevice and pitting corrosion at even moderate temperatures. Super duplex stainless steels present superior corrosion resistance to duplex stainless steels in seawater applications, and provided weld quality is maintained, pitting should not occur in seawater up to about 40°C. The operational limit stipulated in the Norsok Standard (M-001, Rev.2, November 1997) is one of the most conservative for unprotected super duplex service and is more restrictive than most operators’ own requirements. The maximum operating temperature is set at 15°C and the maximum … Continue reading Duplex piping and seawater

Mechanical, PIPINGLeave a comment

Make temporary flange for Hydro-test or Blind as ASTM A 694.

Amarine Antonio

A specification for steel forgings such as ASTM A694 covers a wide range of strength grades from F42, with a minimum specified yield strength of 290 MPa, to F70, with a minimum specified yield strength of 485 MPa. The compositional limits are given in ASTM A694 (product analysis) are ≤0.3% carbon 0.13-0.37% silicon and ≤1.50% manganese. Additionally, the steel may contain micro-alloying elements, i.e. it may be a micro-alloyed (or high strength low alloy) steel; alternatively, Cr-Ni-Mo-V low alloy steel, ASTM A707 Grade L5, may be used. Particularly for small valves and thin section sizes, it may be expected that … Continue reading Make temporary flange for Hydro-test or Blind as ASTM A 694.

WELDING, WELDING METALLURGYLeave a comment

Stainless steel and PWHT – Post weld heat treatment

Amarine Antonio

Most austenitic stainless steel weldments do not require post-weld heat treatment. For those that do, the heat treatment temperature should reflect the particular concern that is being addressed. The necessity for any type of heat treatment of austenitic chromium-nickel steel weldments depends largely on the service conditions encountered. For some applications, heat treatment is used to impart the greatest degree of corrosion resistance possible, eg by solution treating to homogenize the composition or stabilizing, to minimize the risk of sensitization during subsequent elevated temperature exposure. In other applications, heat treatment may be used for stress relieving. This may give more … Continue reading Stainless steel and PWHT – Post weld heat treatment