What are the main causes of imbalance in rotating machinery?

Unbalance in rotating machinery can be a scary, and sometimes dangerous occurrence. The machinery will cause vibrations that can be detected by a balancing machine. There are many reasons this could occur due to the sensitivity of the machinery. Read about the causes of unbalance in rotating machinery below:

Loose parts

Loose parts, such as bolts and screws, within the machinery can cause unbalance due to the lack of support of other parts. However, unbalanced rotating machinery will emit vibrations, sometimes quite severe, that could also cause parts to loosen.

Overhung weight

Overhung weight refers to an overload of perpendicular weight at the ends of a shaft. This overhung weight causes unbalance due to the gravitational pull that bends the shaft that sits within the rotating machinery. If it is not balanced as soon as possible, it will cause major wear and tear.

Operating temperatures

The operating temperature of the machinery can also cause unbalance. Hot and cold air running through the machinery will make it expand and shrink, respectively. This change in the parts can result in an unequal force which would result in unbalance.

Debris or moisture

If the machinery is left standing for an extended period, debris such as dust could build up on its parts. Dust is a major cause of imbalance and regular maintenance should take place to ensure all parts are clean. If there is any moisture in the air, the parts of the machinery could corrode, another factor that could influence imbalance in the machinery.

There are two types of chrome plating – hard chrome plating and thin dense chrome plating – that can be applied to the surface of various metals. Hard chrome plating requires a thicker layer of chrome on the surface of a metal than thin dense chrome plating. Hard chrome plating is usually used for engineering purposes which requires the metal to be strong and durable. Read more about hard chrome plating below:

What is the process?

There are various types of chrome plating such as crack free chromium, micro-cracked chromium, porous chromium and micro-porous chromium. Each of these hard chrome plating types are required to follow a different plating process. For example, micro-porous chromium involves the use of inert suspended particles. Porous chromium, on the other hand is achieved by etching electrodeposited chromium. The hard chrome plating is then finished off with further polishing or grinding to improve the surface.

What is it used for?

Hard chrome plating is used in applications that expose the material to a large amount of wear and tear such as high temperatures or a large amount of pressure. The thick layer of chrome is required for the protection of the metal, whether it be regular steel, stainless steel, aluminium or another material. The hard chrome plating process also reduces friction and can sometimes improve corrosion resistance. The thickness of the chrome plating can vary between 0.020mm and 0.127mm for hard chrome plating, depending on the application it is intended for.

Chrome and chromium may sound like the same thing, but they are not. However, these two materials are related to one another. There is no chrome without chromium. Read below to find out the difference between chromium and chrome:

Chromium

Chromium is a silver-blue coloured hard metal element found in chromite. The element is used in the manufacturing of stainless steel, production of various alloys and the compounds found in chromium can also be used to create dye as they all have vivid pigments. The most common use for chromium is for chrome plating. Two types of chromium are used for this; Hexavalent and trivalent. Although, hexavalent chromium is classified as a highly toxic element, so most chrome plating is created using trivalent chromium.

Chrome

Chrome is the term used to describe an electroplated chromium layer over another metal. Normally, trivalent chromium is used to create a thin or thick layer of chrome to cover another metal for protection. Chromium’s hard, anti-corrosive properties make it the perfect element to use for plating. If a thick layer of chrome is used, this is referred to as hard chrome. Hard chrome is used to plate industrial equipment used in applications that would expose the material to high temperatures or a lot of pressure. A thin layer of chrome is referred to as thin dense chrome or decorative chrome and can be used as trimming for cars or motorbikes. It is not as strong as hard chrome plating.

Most welding services will offer hardfacing to clients, but often people are confused as to what it is. It is confusing to weigh the benefits of a service when you aren’t sure what it’s for. If you are unsure what hardfacing is, read all about it below:

What is it

Hardfacing is the act of spraying materials, in the form of powder, welding rods or tubular rods, onto a surface. These materials include nickel-based alloys, chromium carbide alloys, cobalt based alloys and more. These materials are used because they are durable. They are sprayed onto surfaces that are already worn or are prone to wear. Hardfacing applies thick layers of these durable materials onto the wear-prone surface in order to increase the longevity of the component by protecting it.

Applications

Hardfacing is generally applied by means of thermal spraying, welding processes and more. thermal spraying can be used for hardfacing components that have already undergone wear. It is preferable for use on materials that should not undergo major heat distortion. The layer of hardfacing applied by means of thermal spraying is usually 0.3 mm. Welding process such as arc, MIG and TIG can be used for hardfacing. These processes can be used to apply coating between 1 to 10 mm thick. After the welding processes have been used for hardfacing, a finish should be applied to the component.