Welding Terms Part-10 (S)

Dear Readers,

This continues Part-9. Knowing the list of welding abbreviations is crucial. Recognizing these abbreviations is the initial step in blueprint reading. Therefore, understanding the terms used in welding is essential.

Scarf – The chamfered surface of a joint.

Scarfing – A process for removing defects and checks which develop in the rolling of steel billets by the use of a low velocity oxygen de-seaming torch.

Scarf Joint – A form of butt joint.

Scratch Start TIG – A common method of striking an arc in the TIG welding process which involves dragging the tungsten electrode across the surface of the metal.

Seal Weld – Any weld designed primarily to provide a specific degree of tightness against leakage.

Seam Weld – The seam is right where the two plates, strips, etc. touch. It is important that you get half of the Weld Pool on each side of the seam.

Semi-Automatic Welding – MIG is an example. The machine runs the wire (Filler Metal) and supplies the Shielding Gas automatically, but it takes a person to pull the trigger and manipulate the gun to make the weld.

Self-Shielded Flux Cored Arc Welding (FCAW-S) – A flux-cored arc welding process variation in which shielding gas is obtained exclusively from the flux within the electrode.

Series Welding – A resistance welding process in which two or more welds are made simultaneously by a single welding transformer with the total current passing through each weld.

Sheet Separation – In spot, seam, and projection welding, the gap surrounding the weld between faying surfaces, after the joint has been welded.

Shielded Metal Arc Welding (SMAW) – A process that welds by heat from an electric arc, between a flux-covered metal electrode and the work. Shielding comes from the decomposition of the electrode covering.

Shielding Gas – Protective gas used to prevent atmospheric contamination.

Shoulder – The portion of the prepared edge of a member to be joined by a groove weld which is not beveled or grooved.

Shrinkage Stress – Stress remaining in a structure or member as a result of thermal and/or mechanical treatment.

Shrinkage Void – A cavity-type discontinuity normally formed by shrinkage during solidification.

Single Impulse Welding – The making of spot, projection, and upset welds by a single impulse of current. When alternating current is used, an impulse may consist of a fraction of a cycle or a number of cycles.

Single-Welded Joint – In arc and gas welding, any joint welded from one side only.

Size of Weld – The size of weld refers to the dimensions of the weld, typically its diameter or width and depth, depending on the type of weld.

Skip Weld – A sequence used to control warping (distortion).

Skull – The un-melted residue from a liquated filler metal.

Slag – when the Flux on a welding Rod melts it produces the Shielding Gas to protect the weld, and then forms a hardened protective coating over the weld. It is called Slag.

Slag Inclusion – Slag inclusions are one of the main Weld Defects. If you don't properly clean the Slag from a Bead, you run the risk of it becoming part of the weld when you run the next bead.

Slot – Slot welds are just like Plug Welds except instead of being round, they are elongated. (Long and narrow/ Elongated Hole).

Slugging – The act of adding a separate piece or pieces of material in a joint before or during welding that results in a welded joint not complying with design, drawing, or specification requirements.

SMAW – Shielded Metal (stick) arc welding uses a consumable electrode that has a solid metal rod in the core. The rod and electrode melt down and become part of the weld. The electrode is flux coated to protect the weld from contamination.

Soldering – A joining process using a filler metal with a liquidus less than 840 °F and below the solidus of the base metal.

Solid State Welding – A group of welding processes which produces coalescence at temperatures essentially below the melting point of the base materials being joined, without the addition of a brazing filler metal. Pressure may or may not be used.

Solidus – The highest temperature at which a metal or alloy is completely solid.

Spacer strip – A metal strip or bar prepared for a groove weld and inserted in the root of a joint to serve as a backing and to maintain root opening during welding. It can also bridge an exceptionally wide gap due to poor fit up.

SPALL – Small chips or fragments which are sometimes given off by electrodes during the welding operation. This problem is especially common with heavy-coated electrodes.

Spatter – Metal particles expelled during welding that do not form a part of the weld.

Spatter loss – Metal lost due to spatter.

Spot Weld – (also known as resistance spot welding) is a resistance welding process. This welding process is used primarily for welding two or more metal sheets together by applying pressure and heat from an electric current to the weld area. Used on thin gauge metal like car bodies.

Spray Transfer – In arc welding, a type of metal transfer in which molten filler metal is propelled axially across the arc in small droplets.

Spray Welding – Another term for spray arc welding or GMAW.

Square-Groove Weld – A type of groove weld.

Staggered Intermittent Fillet Welding - Two lines of intermittent fillet welding on a joint in which the fillet weld increments are one line are staggered with respect to those in the other line.

Standard Temperature and Pressure (STP) – An internationally accepted reference base where standard temperature is 0 °C (32 °f) and standard pressure is one atmosphere, or 14.6960 psia.

Steel – Steel is iron ore mined from the ground, purified in blast furnaces, and then carbon added in its molten stage.

Stick Welding – Same as Shielded Metal Arc Welding (SMAW)

Sticking – It is the occurrence when the rod sticks to the steel instead of starting an arc. It's usually caused by the heat not being hot enough, or the wrong ROD angle.

Stick-Out – The length of nonmelted electrode extending beyond the end of the contact tube in continuous welding processes.

Stitch Welding – The use of intermittent welds to join two or more parts.

Stinger – Another name for the SMAW electrode holder.

Stored Energy Welding – The making of a weld with electrical energy accumulated electrostatically, electromagnetically, or electrochemically at a relatively low rate and made available at the required welding rate.

Straight Polarity – Direct current arc welding where the work is the positive pole.

Stress Corrosion Cracking – Failure of metals by cracking under combined action of corrosion and stress, residual or applied. In brazing, the term applies to the cracking of stressed base metal due to the presence of a liquid filler metal.

Stress Relief Heat Treatment – Uniform heating of a welded component to a temperature sufficient to relieve a major portion of the residual stresses.

Stress Relief Cracking – Cracking in the weld metal or heat affected zone during post-weld heat treatment or high temperature service.

Stringer Bead – A weld bead made without transverse movement of the welding arc.

Stud Welding – A process for attaching a fastener, bolt or nut to a metal base. Fasteners attached during the stud welding process are usually threaded, unthreaded or tapped variety.

Submerged Arc Welding – A process that welds with the heat produced by an electric arc between a bare metal electrode and the work. A blanket of granular fusible flux shields the arc.

Substrate – Any material upon which a thermal-spray deposit is applied.

Surfacing – Welds used to build up worn down equipment to its original form. A good example is a bulldozer bucket tooth.

Synergistic – An action where the total effect of two active components in a mixture is greater than the sum of their individual effects.

Code of Engine Oil

Dear Readers,

As you are aware, water is important to humans and their livelihoods; similarly, Engine oil is essential for an engine. Not only does it lubricate engine components, but it also cleans them and protects them from corrosion.

When purchasing engine oil, you will see numbers like 15W-40, 20W-40, and 5W-30 printed on the containers. This information is crucial for both two-wheeler and four-wheeler owners and drivers. Engine oil usage depends on vehicle operation and weather conditions, such as daytime or nighttime, summer (hot) or winter (cold), and flat or mountainous roads.

Therefore, the specifications of the oil are based on research findings related to these factors. This is why the engine and driving conditions are two crucial factors in determining the right engine oil for your car. Individual oil products are labeled with a range of temperatures indicated in degrees Celsius to specify their suitability for vehicle operation. For instance, oil marked as 15W-40 is ideal for vehicles operating in hot weather. Conversely, in colder climates, using oil with a rating of 5W-30 would lead to better engine performance.

SAE (Society of Automotive Engineers) is a global standards organization that grades engine oils based on their viscosities for classification..

The engine oil grade is represented by an alphanumeric code, commonly formatted as XW-XX. Let us clarify what each character signifies.

The "W" stands for WINTER, and the number before the "W" indicates the oil's viscosity at low temperatures, or when the engine is cold. Generally, a lower viscosity means better pumping and flow capabilities in colder temperatures. The number following the hyphen (-) indicates the oil's viscosity at normal operating temperatures, which is approximately 100 degrees Celsius in an engine.

For example, 10W-30. The 'W' indicates winter, while the number 10 signifies the oil's thickness at lower temperatures or before starting the engine.

The lower the viscosity of an oil, the better it can be pumped and flow in cold temperatures. Therefore, in extremely cold conditions and during engine start-up, 0W oil flows more quickly than 5W oil, allowing it to reach crucial engine components such as pistons, valves, and cylinder walls more efficiently.

Whereas the number 30 after the hyphen indicates the oil thickness at normal engine running temperature.

Consider using oils with higher viscosity ratings (like 40 or 50) for better protection against high temperatures.

Next time you need to change your engine oil or are thinking about purchasing oil, make sure to check your vehicle's owner's manual for the recommended oil grade. I hope this article has been helpful to you. Having a basic understanding of this process can instill a sense of confidence.

SWL

Dear Readers,

On a construction site, you may often notice SWL warning messages on lifting tools and tackle. SWL stands for Safe Working Load. Understanding key terms like Safe Working Load (SWL) and Working Load Limit (WLL) is important for ensuring safety, efficiency, and adherence to best practices in material handling.

SWL is very important and essential for rigging & hoisting works during construction activities, and sometimes stated as the Normal Working Load (NWL). 

It’s the mass or force that lifting equipment, a device, or an accessory can safely handle to lift, hold, or lower a load without the risk of breaking. This is usually marked on the equipment by the manufacturer and is often set at 1/5 of the Minimum Breaking Strength (MBS), though other fractions like 1/4, 1/6, or 1/10 may also be used.

The SWL is determined by dividing the minimum breaking strength (MBS) of a component by a safety factor assigned to that type and use of equipment. The safety factor generally ranges from 4 to 6 unless a failure of the equipment could pose a risk to life; in that instance, the safety factor would be 10.

For example, if a line has an MBS of 1,000 pounds and a safety factor of 5, then the SWL would be 200 pounds. 1000/5 = 200.  

Thumb Rule for Determination of SWL of Wire Rope Slings:

SWL = 8*D2; in Tons; Where D diameter of the rope in inches.

Example: 

    1 Inch diameter rope 1*1*8 = 8 Tons 

    ½ inch diameter rope 0.5*0.5*8 = 2 Tons

Another way to calculate the SWL of any wire rope is by 

    1. Obtained the Breaking strength of the wire rope as per the class.

    2. Consider the Safety factor (Generally taken as 5 for wire rope, except taken as 10 when used for lifting a person)

    3. Divided the breaking Strength by the factor of safety.

Whether you’re an experienced engineer, a safety officer, or just starting out in the industry, understanding these concepts can make a big difference in creating a safer workplace.