Stainless steels are iron-based alloys that contain a minimum of 10.5% chromium.  This chromium reacts with the air and forms a very thin but very tenacious chromium oxide layer which is what prevents stainless from rusting. There are 5 types of stainless steels that are categorized depending on additional alloying elements.  One thing they all have in common is the minimum chromium content of 10.5%. The five types are: Austenitic Stainless Steels Ferritic Stainless Steels Martensitic Stainless Steels Duplex Stainless Steels Precipitation Hardening Stainless Steels Out of these five, austenitic stainless are the most common and familiar types of stainless steels. They exhibit … Continue reading Stainless steel welding and sensitiztion

Hydrogen Induced Cracking (HIC), also called hydrogen assisted cracking (HAC) and cold cracking, is a common welding defect when welding heavy steel sections and steels with high carbon content. In the above mentioned article we explained that you need three things in order to have cold cracking: source of hydrogen, susceptible microstructure and a certain level of stress.  If you can eliminate one you eliminate the potential for cold cracking.  When we ignore this, whether by choice or by ignorance, we are in trouble.  However, many weldments fail due to hydrogen induced cracking even when good welding procedures are in … Continue reading Hydrogen Induced Cracking (HIC) in welding

Today we’ll cover 5 more very important concepts that are governed by the AWS D1.1 Structural Welding Code (Steel).  These concepts can show up as questions in the Certified Welding Inspector (CWI) Exam. As stated in our article from last week, in this exam you don’t have to explain your answers, you simply have to choose the right answer (multiple choice exam). As long as you can find the answer in the codebook you are good. However, it is very important to know why the code imposes certain limits and requirements. Below are 5 more fundamental principles that must be … Continue reading CWI welding inspector notes

Buried-Arc Transfer The arc in carbon dioxide is very forceful. Because of this, the wire tip can be driven below the surface of the molten weld pool. With the shorter arcs, the drop size is small, and any spatter produced as the result of short circuits is trapped in the cavity produced by the arc—hence the name buried-arc transfer. The resultant welds tend to be more highly crowned than those produced with open arcs, but they are relatively free of spatter and offer a decided advantage of welding speed. These characteristics make the buried-arc process useful for high-speed mechanized welding of thin … Continue reading Buried arc transfer mode in welding

New updates on ASME IX – 2019: Using qualification test coupon qualified in 2G, or 1G-Rotated position can develop a WPS to weld with “All” positions in production. ***Flashback to the ASME IX – 2015 & older: The Supplementary essential variable QW-405.2 applies to the test weld coupon when the Notch toughness tests are required by the applicable Fabrication/ End using Codes (Ex: ASME B31.3). In this case, the QW-405.2 will supersede the Non-essential variable QW-405.3 (Changes of weld progression), QW-405.2 becomes an essential variable and requires that a change from any position to Vertical uphill progression requiring Re-qualification of … Continue reading ASME IX QW-405.2 Position variable

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