Stainless steel discolour (sugaring) in welding
We receive several calls about welding stainless and the beautiful rainbow colors, or lack thereof, on the weld and heat-affected zone. Is the tinting an indication of quality? Are these colors acceptable? Do they show that the weld had enough heat to penetrate? Why do they need to be cleaned? The questions are endless. If you are one of the thousands that base their quality standards on Instagram posts please stop right now. All the beautiful pictures of stainless welds are emphasizing the beauty of the rainbow colors in GTAW and GMAW welds. This is producing a false expectation and the impression that … Continue reading Stainless steel discolour (sugaring) in welding
Heat treatment on TMCP steels
In marine, O&G, MOU construction: A large amount of high strength, heavy wall pipe is manufactured using a thermo-mechanically controlled processed (TMCP) steel plate. It is generally accepted that these steels are not designed for subsequent PWHT and may suffer some degradation in their mechanical properties when re-heated above critical temperatures. A number of standards, specifications and technical publications acknowledge the influence of PWHT on mechanical properties of the TMCP plate, but provide limited guidance (depend on supplier quality) on how it will affect the properties. Others refer directly to a detrimental effect, such as BS 4514-1, which states “when PWHT … Continue reading Heat treatment on TMCP steels
Preheating temperature distance range
Preheating is the requirement from both WPS Standard (Ex: ASME IX, AWS D1.1) and End using code (ASME 31.3, ASME VIII). The calculation and investigate on this item have been discussed in previous articles. In this article, we would like to introduce some ways to check the Preheating temperature during site surveillance: 1st – Follow WPS guideline: Ex: WPS 2nd – Specification of the project: Some project specs will somehow mention some certain requirements on this item. Ex: Specification mentions: 3rd – Reading in End using Code (Ex: AMSE B31.3): Preheating: the application of heat to the base material immediately before or … Continue reading Preheating temperature distance range
What is Piping Leak test
LEAK TEST Prior to initial operation, and after completion of the applicable examinations required by para. 341, each piping system shall be tested to ensure tightness. General Requirements for Leak Tests Requirements in para. 345.2 applies to more than one type of leak test. Preparation for Leak Test: 345.3 will be followed as below guide chart: How many Types of LEAK TEST? + Para 345.4 Hydrostatic Leak Test + Para 345.5 Pneumatic Leak Test + Para 345.6 Hydrostatic-Pneumatic Leak Test + Para 345.7 Initial Service Leak Test + Para 345.8 Sensitive Leak Test + Para 345.9 Alternative Leak Test Record: + Para 346 RECORDS Document refer ASME B31.3 – 2019 Continue reading What is Piping Leak test
Hot pass in Welding terms
There are certainly many answers for what exactly does HOT PASS means in welding terminology and from where it actually evolved. Different people had a different opinion and they are as below mentioned. It is to fill the weld bevel. It is to melt and float out the wagon tracks left after the root pass. To release trapped gases, hydrogen entrapment at root weld to minimize the risk of Hydrogen induction cracking (HIC). A significant other is that a large majority of pipeline welds are done in a clamp and under some sort of stress. A root bead and hot … Continue reading Hot pass in Welding terms
Electrode flux types and selection (Part 2)
A lot more depends on the selection of the electrode type for successfully carrying out weld with SMAW process. A wrong selection of electrode type may lead to more defects, more repairs. The selection of the correct type of electrode coating results in weld metal with desired quality characteristics at low cost. In general, the welding electrode is selected in such a way that characteristics of weld metal are similar to or better than the base material while keeping in mind the welding position and weld joints design as they significantly affect the properties of the weld. The covering of … Continue reading Electrode flux types and selection (Part 2)
Electrode flux types and selection (Part 1)
CHOOSING THE RIGHT ELECTRODE FOR YOUR NEEDS It is important to consider both materials and technical aspects when selecting stick electrodes. BRIEF OVERVIEW Type, Name, Definition R, RR, Rutile: Standard electrode for universal use, fine to medium droplet transfer, good mechanical properties, welding positions PA, PB, PC, PE, PF, (PG limited use only). RB, Basic-rutile: Use as a combination of achievable, high toughness values and universal use with increased demands on the welder and the seam finishing work. B, Basic: Use for the requirement of high mechanical properties, average to coarse droplet transfer, poorly detaching slag, possible in all positions, please allow for redrying of … Continue reading Electrode flux types and selection (Part 1)
Rimmed Steel, Semi-killed Steel, Fully killed steel
Some low-carbon steels are available in three grades: “rimmed”, “semi-killed”, and “fully-killed”. The terms themselves are derived from the action of the steel when it is poured into an ingot mold after leaving the furnace. In terms of welding, they indicate whether or not there is oxygen in the steel which may cause weld porosity when certain welding processes are used. All carbon steels contain some oxygen. The very nature of the furnaces in which they are made makes this inevitable. It’s what happens to the oxygen when a weld is made that is significant. When a rimmed steel is welded, some … Continue reading Rimmed Steel, Semi-killed Steel, Fully killed steel
Wire electrode specifications
Flux-Cored Electrodes’ Usability Designators: What Do They Mean? Q: I am a new salesperson for a welding supply company. I have noticed that the AWS classification number for many of the flux-cored wires we carry are the same on the front end, but then have different dash numbers on the back end. Some example numbers are E71T-1, E71T-8, E71T-9, E71T-11, etc. Some wires even have two or three numbers on them. I have heard these “dash numbers” called performance capabilities numbers. But what exactly do they mean? Also, how can some wires have more than one AWS number? A: The dash numbers you … Continue reading Wire electrode specifications
AMARINE 