Structural failure integrity, weld cracks


collage of images of metal fatigue failure repair, aluminum and iron cast welding, industrial corrosion service

JW Portable Welding & Repairs welds cracks causing structural failure or structural integrity failure in damaged casts, heavy machinery and equipment, aluminum handrails and stainless steel handrails. The structural failure issues are very common for production machinery, heavy construction equipment and in variety of casts.

We also repair corroded structural elements that are at risk of loosing structural integrity. We repair rusted posts, columns, and steel handrails. It is important to realize that risks of construction elements loosing structural integrity not only causes increase risks of severe building damages. But, also can cause injuries and deaths. That is why we treat them with at most respect.

Call us, text us or email us for traditional and advanced welding services. And leave us your feedback on our google profile.

3 main reasons for structural failure, metal & weld cracks

In short evaluations of reasons for structural failures, we have to clearly differentiate between loosing of structural integrity of equipment from structural integrity of construction elements. Whereas corrosion is the most popular reason for structural failure of construction elements experienced by property owners. The equipment and machinery are prone to loosing the structural integrity due to rather mechanical factors.

Excessive vibration causes structural failure

Excessive and cumulative vibration is one of the reasons for structural failure of production machinery and variety of casts. In fact, the excessive vibrations due to misalignment, severely damaged bearings, and balancing issues cause structural failure. The weld cracks and elongated metal cracks develop in such environment. These metal cracks and weld cracks usually begin from the plane where the vibrating element meets with rigid element. The along this plane the settles in causing metal fatigue. Then the metal cracks or the weld cracks and the stress is reduced to by some degree. Unfortunately, if the reason for excessive vibration is not eliminated than the cracks will elongate. The elongated cracks will cause a complete structural failure of the equipment

Impact and equipment overload

Excessive equipment overloads and impacts also cause structural integrity failure. In contrast however, these metal cracks and bends start from the place of impact or from the acting tool. Moreover, these initial cracks do not progress quickly. Unless the operator overloads the equipment once again or again causes the impact these cracks will not elongate fast. Although, these cracks usually do not cause additional vibration, they definitely cause severe misalignment due to excessive bending. As much as we would like to blame the operator for equipment’s damages, at the same time we have to realize that these operators production regime or sometimes inadequate equipment capabilities.

Corrosion of construction elements

Excessive and deep corrosion can cause structural integrity failure in structural elements made from steel. Same problems affect elements made from aluminum and stainless steel. The most popular is rust settling in variety of steel handrails, posts and columns.

The repair of corroded bottom of steel column, 6 inches x 6 inches improved the structural integrity of this HSS column. JW Portable Welding & Repairs, 2021
The repair of corroded bottom of steel column, 6 inches x 6 inches improved the structural integrity of this HSS column. JW Portable Welding & Repairs, 2021

Although aluminum and stainless steel are treated by many as materials that do not corrode. But unfortunately they corrode in specific situations. The excessive corrosion can cause complete structural failure of aluminum tanks used in water purification systems. And, variety of poor quality stainless steel elements also can corrode if exposed to caustic environments

In order to develop more inside regarding structural failure of steel structure please read this article

Every owner of heavy equipment should read these 5 causes of equipment structural failure

Planning of improving equipment structural integrity

Proper planning of equipment’s structural integrity repair is extremely important. Particularly the proper function of equipment determines if certain elements of the equipment must be exchanged or repaired. These considerations involve the cost of repairs as well as the need of proper element’s alignment that will determine the equipment functionality. Additionally, the remaining equipment utilization time and its potential replacement cost will determine the extend of repairs.

The replacing the severely damaged element is indeed preferable, but sometimes impossible due to lack of spare parts for the older equipment. The replacement of structurally damaged parts will cause minimal misalignments that usually can be easily adjusted.

In case the replacement of element is impossible

In case the element can not be replaced due to variety of reasons, the second option would be to fabricate the custom element in the same sizes as the original one. Unfortunately, such weldment would have to be later certified. And the cost of such fabrication could be very significant.

The last option to improve structural integrity is to weld metal cracks and cracked welds. This welding process should not disturb the equipment’s alignment. Since welding process causes tensions and warpage, these forces could be used by skilled welder in order to align the damaged element into proper position.

Please contact us to fabricate the equipment’s damaged element or to weld metal cracks and cracked welds

Planning to improve construction element structural integrity

As mentioned above the construction elements can loose their structural integrity to corrosion. The size and location of corroded material will determine the remedy methods. If the size is damages is significant and the corrosion is located in load bearing parts of the construction element than such element should be replaced.

Fortunately, fabrication of corroded element will not be a problem. However the actual replacement cost could be very significant due to necessary supports replacing the support provided by damaged element. Additionally, variety of safety precautions and crane involvement will contribute to increased cost.

It is important to realize that most of the construction element corrosion accumulates at the bottom of columns, bottom of posts and bottoms of handrails. Therefore we provide a replacement service focused on the damaged portion of the damaged column or posts. In this way, we eliminate the excessive cost of replacing the whole element.

Contact us to upload pictures of damaged by corrosion construction elements.

The welding of cracks improves structural integrity

Our mobile welding service or portable welding service offer repairs of structural integrity of machinery and equipment. We not only repair metal cracks and weld cracks but also exchange severely damaged elements and correct misalignments. In particular our service offers:

  1. on site aluminum cracks repair,
  2. steel cracks repair on site, and
  3. on site stainless-steel cracks repair.

Extremely large crack on the steel press leg repaired using fish plate by JW Portable Welding & Repair, London, Ontario, 2017

Extremely large crack on the steel press leg repaired by welding a “fish” plate by JW Portable Welding & Repair, London, Ontario, 2017

The nature of metal cracks’ repairs and weld cracks’ repairs depend on the length of the crack and its depth, its location, thickness of metal and the type metal. Generally speaking, the ideal scenario involves grooving or removing the crack completely. Then welding the groove from outside and inside. And, then welding the “fish plate” from outside on top of the welded crack.

Two fish plates welded on the crane improved structural failure. Top view. JW Portable Welding & Repairs 2021
Two fish plates welded on the crane improved structural failure. Top view. JW Portable Welding & Repairs 2021

Real life challenges in structural failure repairs

Unfortunately, ideal situations for improvement of structural failure by welding cracks do not happen too often. Either the depth of the metal crack is too deep or crack’s location is not completely accessible. Most often the end of the crack is also not traceable. Moreover, welders can not weld the crack’s root from inside since the equipment would have to be taken apart. This is additional costly proposition.

With this in mind, instead of doing a patchy work at client’s cost, JW Portable Welding & Repairs uses technology. This technology involves advancements of welding consumables, best welding practices and custom “fish plates”. In this way, we give the best effort of structural failure repair. However, in spite of our best efforts our repairs will fail if the client will not eliminate the original cause or causes for element’s structural failure.

Here is the link to our 2021 flagship project regarding welding of cracks on cranes.

Advanced welding rods and wires

Our advanced welding rods have gained us many new customers. In view of our visitations to welding shows in North America, we have developed selection of welding rods and wires more suitable for performing the metal crack repairs. Our selected collection of advanced welding rods involve alloys resisting higher vibration, impact and friction resisting alloys, deep penetration rods and high tensile rods.

Preheating and root penetration

First, we begin with monitoring the heat during the preheating. Then, we continue the heat monitoring during the welding process itself. Each type of metal requires different procedures in this regard.

Most importantly, we begin welding with selected root penetrating rods or wires according to selected welding technique. Please keep in mind, mild steel, stainless steel and aluminum require different welding technology for delivery of filler metal for the root penetration. They also require adjusted welding technique pending the type of rod or wire. In case of stainless steel and aluminum the root penetration rods do not exists and therefore we usually Tig them. Unfortunately, the budget constrains does not allow to use Tig technology to root welding of cracks in steel.

Joint modification and/or groove modification improves strength of weld

Prior root preparation, we tend to consider joint modification and/or groove modification. This technique could produce more vibration resistant weld. It is paramount to understand that joint modification and groove modification directly influence the strength of the weld and its resistance to cracking.

Understanding the forces acted on the broken joint is paramount to modify the joint in order to increase the element’s structural integrity. Point often overlooked, is our engineering and millwrighting background as well as long experience in repairs of such damages.

Groove welding accumulates heat and could cause additional structural failure

For deposition of groove filler, a different welding rod or wire is selected. We could also use a different welding technology to increase efficiency of the whole process. However, by increasing efficiency we do not sacrifice quality and strength of our repairs.

The potential damages can occur due to excessive heat accumulation during welding and then excessive cooling. Excessive heat accumulation and excessive cooling could cause weld cracks and material cracks too. Therefore, unexperienced welders fix the weld cracks and metal cracks the best way they can. But, unfortunately create plenty micro cracks surrounding the welded main crack. This is one of the reason for creation of additional crack parallel to the old crack.

Another point is that heat accumulation will cause warpage. Alternatively, excessive heat accumulation can cause even complete material disintegration as it is in case of aluminum. The heat dispersion techniques on stainless steel could eliminate extreme temperature’s amplitudes. However, we prefer stringent temperature regime during welding. The heat dispersion often assists in avoiding inadvertent damages due to excessive warpage.

Welding a “Fish Plate” directly improves the structural integrity

The whole welding repair process ends with welding a “fish plate” on top of the repaired steel crack. The proper shape “fish plate” that is welded properly should support the repaired crack in about 70%. However, this usually means that the “fish plate” shape covers not only the repaired crack but also supports the joint assembly. In general, many factors influence the “fish plate” shape, its thickness and its weld size. We have to consider

  1. the best way to protect the weak spot,
  2. strengthen the immediate area of the crack and,
  3. relocate potential stress to different location.

Once again, we could chose a different rod or a wire for welding in a “fish plate”. The irregular size of the weld will reflect our efforts to relocate the stress to different area.

We recommend comprehensive vibration analysis after extensive crack welding on the heavy machinery or heavy equipment,  since the bearing tolerances could change due to micro-warpage.

Our own improvements of structural failure’s welding repairs

Moreover, we have also improved delivery of our preheating process prior welding and its monitoring. In fact, we use staggering preheating to reduce distortion during welding. Then again, we continuously monitor temperatures during the welding process to reduce the potential of distortion influence on element’s alignment.

In particular, our asymmetrical welds improve the weld resistance to excessive vibration. And, the asymmetrical heat distribution during welding process corrects mechanical alignment of cracked components.

Old British and/or German endings of crack repairs

Another, key point is that we tend to reduce and disperse stress accumulated at beginning and end of welded crack. Although, sometimes we drill holes through these ends, we found out that the location of these holes can not be established precisely. This is due to differences of crack development on the outside and inside. In thick materials there is significant difference in location of crack ends outside position and inside position. That is why, we use 19 century endings developed in Britain and Germany for these ends.

Additionally, we have developed different shapes of “fish plates” for different joint assemblies to increase the fish plates participation in vibration resistance or excessive load caring.

Our advanced technology to repair structural failure of  damaged cast

We are proud of our advanced welding technology in mobile welding of damaged large cast such as: steel cast, iron cast and aluminum cast. Welding large damaged cast is difficult and expensive since it requires a very good welding machine, knowledgeable welder and proper welding rods or wires. Most welding repairs on small damaged cast happens in the shop in a very controlled environment.

Welding of large steel casts with multiple cracks is our specialty. Here is JW Portable Welding & Repair's welder welding large steel cast with sophisticated welding rods. London, Ontario 2017

Welding of large steel casts with multiple cracks is our specialty. Here is JW Portable Welding & Repair’s welder welding large steel cast with sophisticated and very expensive welding rods. London, Ontario 2017

When sending the large broken cast to the shop is technically impossible or impractical due to its size. Or, sometimes too costly than our clients call us. With us on board, our clients avoid extensive disassembly and then assembly time, costly loading and unloading. And then costly transportation to distant location. They avoid also risk associated with transporting the cracked cast. The cracked cast can sustain additional damages due to standard vibration or impact that occurs during transportation,  loading and unloading.

We will weld, in place, their large damaged casts such as steel cast, iron cast and aluminum cast. The ability to repair cracked and damaged casts, in place using our mobile welding services forms our comparative advantage. It is a source of our greatest pride for elimination of structural failure in castings.