In the world of astronautics and space engineering there are many challenges. These also apply when manufacturing fasteners for the space industry.
Satellite and spacecraft fasteners must perform in incredibly stressful environments, yet they also need to be lightweight and highly corrosion-resistant. And because of the unique nature of developing and building spacecraft, many of these parts need to be specially made to outlined specifications.
To support the provision of effective space engineering services, both here in the UK and around the world, our team must work to the most exacting requirements. Even the smallest of defects will threaten the structural integrity of a spacecraft which needs to operate seamlessly under varied and intense stressful conditions.
It is for these reasons and more that each part needs to be rigorously tested to assure the highest quality control.
Performance Characteristics of Aerospace Fasteners
Some of the characteristics which are commonly exhibited by space industry fasteners include:
- High corrosion and oxidation resistance
- High tensile, shear, and fatigue strength
- Lightweight construction (to help optimize lift and minimize fuel costs)
- Operational capabilities in extreme environments (e.g., low and high temperatures and pressures)
- Self-sealing and self-locking capabilities (to prevent leaks and loosening during use)
As we have outlined above, fasteners for the space sector are designed with several prevalent characteristics in mind. To obtain these characteristics precise manufacturing methods must be paired with carefully selected materials and each part rigorously examined and tested to assure the absence of defects.
Some of the common materials used for aerospace fasteners include:
Typically aluminium is used in atmospheric planes. That being said, it also has applications in the space industry because of some of it’s prevalent qualities. However, it often requires additional surface treatment to attain the required properties.
For example, although aluminium rivets are common, achieving aerospace standards for these components requires that the lightweight material be cold-head formed. Unfortunately, even after being subjected to this process, the material remains highly sensitive to temperatures above 250 degrees Fahrenheit, as well as to stress-induced corrosion.
Steel and steel alloys generally have high strength and surface hardness which is ideal for numerous application. However, they are also heavier than other materials so careful consideration musty be used when designing the aircraft.
Additionally, certain types of stainless steel are susceptible to heat damage and failure so again the correct steel with the required properties needs to be carefully paired with its application.
Titanium can be, and occasionally is, used as an alternative to aluminium. It has the advantage of greater strength and heat and cold resistance while being of relative lightness when compared to materials such as steel.
Some of the favourable characteristics include hugh versatility, the ability to maintain their structural and surface integrity in extreme environments, and their resistance to creep factors.
Each fastener must be manufactured to the specifications laid out in the manufacturing brief and then must, when relevant, pass the following tests to strict guidelines to assure the overall quality is adequate.
Generally performed using a specifically dimensioned and loaded object (indenter) into the surface of the material you are testing. This test determines the surface hardness of the part by measuring the depth of indenter penetration or by measuring the size of the impression left by an indenter.
Tensile Strength Test
Tensile testing is used to determine the bahaviour of a sample while an axial stretching load is applied. This test determines the maximum load that a part can withstand.
Shear Strength Test
Shear strength measures a parts ability to resist forces that cause it to slide against itself, for example, if the grain of the fastener metal were to be going across the fastener the part would be liable to break cleanly along the grain should adequate force be placed in that direction.
Fatigue tests measure how the material performs under repeated stressful loading. This allows you to determine the load cycles to failure. Fatigue tests are performed by repeated combinations of cyclic loading in accordance with ISO 3800
A creep-testing machine measures the creep (the tendency of a material after being subjected to high levels of stress, e.g. high temperatures, to change its form in relation to time) of an object. It is a device that measures the alteration of a material after it has been put through different forms of stress.
Corrosion testing is generally performed to evaluate materials for a specific environment or to evaluate means for protecting a material from environmental attack.
Stress-corrosion is a time-dependent process in which a metallurgically susceptible material fractures prematurely due to the synergistic interaction of a corrosive environment and sustained tensile stress at the metal surface
Everything must be done to strict guidelines and standards to assure the highest quality of manufacturing for aerospace parts.
When it comes to the production of fasteners for the space industry the importance is on quality and each part must remain free from even the smallest defects. This is managed through the use of highly skilled and trained professionals and abiding by regulations for international standards.
The UK’s No1 fastener supplier to the space industry
We supply a wide range of industrial and aerospace fasteners for the space industry. Whether standard, metric or custom design we are leading UK experts. AS9120 REV A & ISO9001:2008 approved and SC21 compliant. When it comes to space industry fasteners, we are the team to contact.