Welding, an art that has been around for centuries, has come a long way since its invention. From the early days of blacksmiths hammering metal together to modern-day welding machines, it’s evident how technology has revolutionized this craft. But what about blending welds?

The Superflex abrasive range from Grinding Techniques is a versatile and affordable solution for all your welding needs. It offers a wide variety of products that include an extensive range for surface preparations that will turn anyone into an expert.

Welding is a joining process that permanently fuses materials together. A welder uses heat and pressure to join two pieces of metal or other materials together. The finished weld is known as a weldment or seam, leading onto the next process – achieving a seamless finish with our range of surface preparation abrasive products.

Blending welds is the action of combining two metal pieces together through welding and the grinding down of the weld to produce no visible seam.

Before welding can commence, the workpiece needs to be cleansed of any rust or mill scale that has formed.  The requirement for this application is ideally suited to the Superflex rough cleaning, or non-woven flap disc.  Once the cleaning process is completed you can determine the type of weld that is required.

There are many different welding processes, and each has its own advantages and disadvantages. The type of welding process that is best for a particular application depends on the materials to be joined, the thickness of the materials, the desired strength of the weld, the speed of the process, and the cost. Some common welding processes include MIG welding, also known as Gas Metal Arc Welding and TIG welding, known as Tungsten Inert Gas Welding. Where MIG welding is known to be a low cost yet highly productive method of welding, and mostly used on common metals like Carbon Steel and Alloys, TIG welding is a more precise form of welding and requires a bit more skill, as it results in a neater and smaller weld.

Carbon steel is almost always painted after welding, where Stainless steel usually requires a polished finish. If working on Carbon steel, not all welds need to be removed, as the seam will not always be visible. Stainless steel, like elevator panels, or handrails on the other hand requires a highly refined finish to disguise scratches.

When preparing to blend a weld, it is important to ensure that you are working with a clean, good weld, free from air bubbles or porosity. There should also be no undercut for example, edges that don’t intrude or fold into the surface of the material.

The Superflex range consists of different product options when it comes to blending weld applications. Removing the weld can quickly be accomplished with our Superflex AS30R Professional grinding disc for ease of application and minimal fuss.  We recommend, a criss-cross motion to knock down the high spots when grinding, as you will remove stock quicker and easier without damaging the workpiece around the weld.

It is important to refrain from too much pressure when using a grinding disc, as you wouldn’t want to grind into the weld causing damage that could potentially weaken the weld leading to it needing to be re-worked. In some cases, a used grinding disc might offer the perfect solution, as it will be less aggressive on application. It is important to note that the final required blend will require further rework with a finer grit abrasive product after grinding.

If opting to use only one product, the Industrial and Professional range of Superflex Flap Discs with a multitude of application possibilities on various material, is ideal to remove both the weld and produce the final blend.

As a third option to blend welds, Superflex Fibre Discs can be used. A P80 grit used at a really low grinding angle of about 45 degrees, will blend the weld perfectly. Once satisfied with the finish, you can use a finer grit fibre disc, we recommend either P120 or P150, to remove the scratch marks further. Take care not to use excessive pressure during this application.

The surface is now ready for painting, perfectly prepared using the Superflex range of surface preparation products, however if a mirror finish is required, we recommend using a Superflex Non-woven Medium Flap disc followed by a Superflex Non-woven Fine Flap disc.

Whatever your requirement when it comes to abrasive products, we have you covered.

Contact us today for a bespoke solution to all your application needs.

+27 11 271 6400 | info@grindtech.com | www.grindtech.com

Valve supplier Bilfinger Intervalve Africa (BIA), investigated the steam system of a paper mill to allow for possible improvements that can be made. Top performers in the paper and pulp industry are constantly striving to increase productivity and quality while minimising costs. The main aspects that need to be addressed in achieving operational excellence are a reduction in energy costs, chemical use, production downtime and process variability.

“The correct selection, monitoring and servicing of control valves can result in financial rewards for clients,” he points out.

Underhill mentions that the functions of control valves in the paper and pulp industry are extremely diverse. They range from the required accuracy of the dosing valves, and the tight control and fast-acting requirements of the basis weight valve to the severe service requirements of the power and steam system such as the control of cavitation and noise.

Careful consideration should be given to the selection of a control valve, as the specific function which it needs to fulfil in sizing and style has to be considered, he states.

Underhill explains that the process of selecting the correct size, style and characteristics of a valve is paramount in the initial stages of a project. Incorrect sizing of the control valve could result in the valve not operating in a good control range, leading to the possibility of excessive wear and loss of controllability.

Certain valves have been specifically designed to operate in different applications – incorrect selection can lead to cavitation or flashing damage, excessive plant noise and poor control in areas such as basis weight, affecting paper quality. Valves used in incorrect applications can lead to undesirable process variability.

Control valve assembly consists of three prime components – the valve body, actuator and positioning. These components need to work in harmony with one another to fulfil the client’s control requirements. Poor performance of any of these components can lead to poor control of the process, leading to unacceptable process variability that can seriously affect the user’s bottom line, he explains.

The advent of the smart positioners on control valves, as well as emergency shutdown valves, have resulted in many benefits for the client, Underhill notes. The Fisher DVC2000 and DVC6200 series digital valve controllers add accuracy of the valve position along with valve diagnostic capabilities that will determine the health of the valve.

Using the downloaded information from the device, either from advanced diagnostics or the online performance diagnostics, allows for maintenance programmes to be adjusted to cater for the more problematic valves. This will avoid the removal and stripping of valves that are in good health, which is costly and time consuming, he explains.

Overlaying downloads obtained from valves over time will assist the client in moving to predictive maintenance and reducing expensive stock holding of spares.

In conjunction with control valves, it is important to be aware that good-quality, hand-operated or automated isolation valves should be used in certain applications to protect the control valve, Underhill says.

“Bilfinger Intervalve Africa has a wide range of quality products to fill this role,” he concludes.

Vesconite Bearings is supplying a Georgia-based vertical-turbine pump manufacturer with a 5000-unit blanket wear-rings order, allowing the manufacturer to request low-friction Vesconite Hilube polymer wear rings for 10 of its vertical-turbine-pump models.

The company ordered its first Vesconite Hilube wear rings in 2015 and, after testing, started ordering larger quantities from 2017. In March 2019, Vesconite visited the pump manufacturer and finalised fixed volume requirements and pricing for the blanket order. The company supplies the central and south-eastern USA with pumps for the municipal, industrial, fire and flood-control industries.

The order covers a one-year period and allows the company to regularly draw on the 5000-unit blanket wear rings order. Vesconite Bearings technical sales representative, Charlie Simpson, said: “The company sees the value of using the product and has switched all of its wear rings to Vesconite Hilube ones in all of its own-brand vertical-turbine pumps.”

Vesconite Hilube wear rings allow for extremely close clearances to ensure greater pump efficiencies and are designed for use with mildly acidic or basic liquids.

SCHROEDAHL, a CIRCOR International brand has announced that new, self-modulating TDL Automatic Recirculation Valves (ARVs) are now available in cast material that is more than 35% lighter.

The all-in-one pump protection solutions are designed to keep pumping systems running smoothly in firefighting, refinery, power and chemical applications without cavitation or overheating.

Unlike control valve packages, the self-operated flow-sensitive Schroedahl TDL Automatic Recirculation Valves operate without a separate power supply or any control system and begin protection as soon as they are installed.

The valves combine a high-quality main line check valve and the automatic bypass control system in a new, durable design. The valves’ self-actuated integrated bypass control function ensures minimum flow rate, guarding pumps against overheating and cavitation. The systems provide high pump stability with less vibration and fewer coupling or gear problems. TDL ARVs’ modulation bypass function also offers savings for operators with reduced energy consumption for frequent partial load operation.

Additionally, the bypass check valve prevents reverse pump flow, and allows for parallel pump installations.

The chief geoscientist with leading global mining-tech company IMDEX has issued a clarion call to the mining sector to restore its damaged image and shake off its risk-averse approach as he warned there was widespread ignorance of the scale of the imminent copper supply crisis.

Dr Dave Lawie, Chief Geoscientist and Chief Technologist – Mining Solutions with IMDEX, in an address to geoscience students for the University of British Columbia’s Earth, Ocean and Atmospheric Sciences Department, said the mining sector needed to effectively communicate its role in finding the metals and minerals, including copper, needed in a low-carbon future to address the copper supply crisis. Failure to do so risked the future of decarbonisation and accelerated electrification.

“I have a saying for our industry at the moment. It can’t read the label from inside the bottle. On the outside of the bottle it says, ‘save the world’, but we can’t read the label,” Dr Lawie said.

Finding enough copper to meet future copper supply crisis was a problem “that needs the best minds on the planet to think through.

“That’s the challenge for all of us. Living in a world where we need to talk to people about what the mining industry and geoscience need to do to address the copper supply crisis and save the world is very difficult when I read a survey that says kids think milk comes from a supermarket.

“So, if they think that, try asking them where the copper comes from for their iPhone. “They won’t know; they just won’t have thought of that as a concept. But that’s not their problem. That is our problem.

“We are an incredibly bad industry at communicating with the general public about the copper supply crisis. Terrible, abysmal.”

In a wide-ranging presentation, Dr Lawie compared the likely future demand/supply scenarios for critical minerals to meet net-zero emission targets to those for copper.

“Solar and wind would have to grow 20 to 30 times to deliver the amount of electrification the US needs to decarbonise by 2050 or go carbon neutral by 2050. When I see that I think where is the copper going to come from?” Dr Lawie said.

“To supply the demand for electrify electric vehicles by 2040 we’ll need 42 times the amount of lithium, 25 times more graphite, 21 times more cobalt, 11 times more nickel and seven times more rare earths than we are producing now.

“Now I only find that mildly disturbing because when I look at those commodities I think: Lithium no one’s looked for seriously – ever – and in fact we can find new lithium. Lithium mines we can bring into production. We’re actually finding lots of lithium hard rock deposits at the surface in Australia.

“Australia has increased its hard rock lithium production immensely in just a matter of two or three years. We can respond; it doesn’t worry me at all. Same with graphite. We haven’t really seriously looked for graphite. We’ll fix that. Cobalt is an issue, particularly with mining in the Democratic Republic of Congo, but we can we find 20 times more cobalt, not a problem geologically.

“There are cobaltian pyrite deposits sitting at the surface all through the Curnamona Block in Australia. Increasingly, cobalt is being recovered as a byproduct of nickel laterite mining.”

Cobalt prices have declined this year amid a drop in demand, the possibility of a change in battery technology with less reliance on cobalt, and some miners increasing production.

“Lithium, nickel, cobalt, graphite, manganese, rare earths; don’t worry about it as a geoscientist, Dr Lawie said “Copper? Worry a lot because that is where the problem is going to come.”

He said declining copper grades meant more waste and increased use of water and power to maintain existing supply rates, but current copper mining rates were not enough to cover demand for existing uses without factoring in “the electrification of everything” in a low-carbon future.

Better data from ore body knowledge could help unlock some of the stranded copper assets worldwide that are not constrained by ESG issues. “Barrick has gone back into Reko Diq (gold and copper mine) on the border with Pakistan and Afghanistan.

That tells you something about the risk appetite and that the looming copper deficit is true. Some companies are really making the effort. That is a giant deposit. Given its geopolitical complexity, if it could be (released) it would be a big win for a copper supply of the future,” Dr Lawie said.

“In 2021, we used about 20 to 23 Mt of copper, but some projections have that demand going to 30 Mt by 2030. How on earth are we going to go from 22 Mt of copper to 30 Mt a year? “Kamoa-Kakula copper mine (in the DRC) is the largest mine that has come on line for some time and will produce half a million tonnes a year.

“We need two Kamoa’s a year for the next 10 to 15 years to supply the copper we need to decarbonise. Of those 22 Mt of copper, the four largest producers of it are Chile, Peru, Congo and China. None of those countries you would call great exemplars of democratic governance and stability.

“So, of the current supply, apart from the geological problems of securing more supply and putting it into production, the existing resources are under threat. This is a very finely balanced supply consumption equation.

“We can’t risk copper supply chain delays or our want and willingness to expand solar, and wind electricity production won’t happen.

“If you think that the industry is responding by ramping up exploration budgets massively and getting to work, it sort of is and isn’t. What we’re doing is within the realms of what our industry conventionally does in the face of these things which is not much actually because we’re still risk averse.

“Of course, the more political problems you have in a jurisdiction, the less likely you are to want to go out and spend $10 billion.

“As a reflection of our industry, about half the total global exploration expenditure still is spent on gold.

Next would be copper. The amount of exploration spending on copper is increasing, but not really anything that’s going to make a difference. “The message for my mining industry comrades is, I just wonder if our industry can actually do anything about this?”