Never losing its cool

The use of multibond abrasives on stainless steel keeps the material significantly cooler, making the grinding process more efficient. An additional layer keeps annealing colours from forming and enhances surfaces quality.

The use of multibond abrasives on stainless steel keeps the material significantly cooler, making the grinding process more efficient. An additional layer keeps annealing colours from forming and enhances surfaces quality.

This happens not only to home improvement hobbyists: Lose focus for one second during manual grinding or set the grinding robot to the wrong parameters, and the damage is done: your stainless steel workpiece gleams in shiny bright colours. “Annealing colours are not too unpleasant to look at as long as you do not have to create a uniform surface. However, they also present one crucial disadvantage: Any spot on the surface showing this type of discolouration will begin to rust immediately when exposed to moisture”, says Karl-Heinz Koch, deputy team manager of the laboratory at Klingspor's main production plant in Haiger. Annealing colours are brought about by elevated machining temperatures – as a result of a grinding process that takes too long or is performed at excessive pressure levels. This intergranular corrosion, as this undesired process is referred to in technical terms, involves the bonding of chromium and carbon on account of the added heat. The result is a chromium-depleted zone that is no longer protected against corrosion. Avoiding the time-consuming process of reworking the stainless steel requires that you stay below the critical temperature threshold while grinding. The solution to cooler grinding: Abrasives furnished with multibond. These are also used for high-alloy grades of steel.

  

Annealing colours are a major problem especially when attempting to create a uniform surface.

Less rapid vitrification

“While included in a host of our products, multibond sports an effect that is known to only a select few of our users. It is, in effect, an additional layer of coating. During use, the layer on the tool disintegrates, triggering various simultaneous processes that provide for a cooler grinding process”, explains Koch. However, the substantial reduction of the risk of annealing colours is not the only notable advantage of the multibond. “The processes triggered by multibond reduce the adhesion of the stainless steel to the abrasive’s grain points, slowing down the vitrification of the abrasive to a significant degree”, says Wolfgang Kaiser, head of the Test Trials & Service department, detailing the background. Compared to conventional abrasives, this feature increases both the removal rate and service life.

Ongoing further development

“The larger the surface the user is grinding, the greater the temperature increases. This is where the plus in removal rate is noticeable and pays off in a major way", declares Kaiser. He and his team carried out a slew of tests, pitting products with and without multibond against each other. As with all other products made by Klingspor, the tests also involved testing procedures on different tools delivering various output levels and operating with different operating voltages. “The development process is never fully complete”, stresses Koch.
Even though multibond compounds have been around for nearly 30 years, Klingspor constantly engineers and tests new products based on new materials and optimised dosages. You can never stop as the requirements of our customers constantly change varying with their applications and grinding method. “Who would have thought 15 years ago that robots can now accomplish this task with a “feel” for the material they are machining”, says Kaiser giving an example of ongoing advances.

Rather twisted

Every now and then, multibond products are used for purposes other than those intended. “We recently received word from Portugal, where customers had used abrasives of ours actually intended for grinding stainless steel on giant ship propellers made of bronze”, relates Karl-Heinz Koch, deputy team manager of the laboratory at Klingspor laboratory in Haiger. What is more, the results produced astonished even the most seasoned professionals such as Wolfgang Kaiser, head of the Test Trials & Service department: “Naturally, we test the effects of our products on other materials as well. If used on steel, for instance, multibond does not make a measurable difference. This is why we were amazed to learn that the effect on bronze was entirely different.” Apparently, multibond added noticeable value in this application scenario - an effect that was previously unknown. “Bronze has a slight tendency to stick In contrast to standard grinding discs, which will quickly clog on account of this disposition, the multibond of the discs used in Portugal acted as a release agent, reducing sticking significantly.”

Usage:

Tip 1:

Never use abrasive tools on normal steel first before using them on stainless steel!

Tip 2:

Make sure to thoroughly remove grinding dust particles from all surfaces.

Tipp 3:

Always protect stainless steel surfaces from fountains of red hot sparks!

 

Abrasive belts

The CS 409 Y delivers a highly aggressive grinding behaviour thanks to its self-sharpening zirconia alumina.

Designed for work on stainless steel, this abrasive belt with cloth-reinforced backing is available in grit sizes 40, 60, 80, 100, 120, 150, and 180.

 

Fibre discs

Operating with a high level of aggressiveness, the self-sharpening CS 570 fibre disc is also suitable for machining aluminium.

Just as self-sharpening and exceptionally aggressive, the FS 966 ACT manages to convince with its exceptional service life, especially when used for heavy-duty applications.