Corrosion damage to a lattice boom chord can be repaired by welding in many cases, provided the damage has not compromised the structural integrity of the base material beyond a repairable threshold. Specialist welders trained in high-grade crane steel can restore corroded chords to their original load-bearing capacity. The sections below address the most common questions crane operators and fleet managers have about this repair process.
What types of corrosion damage affect lattice boom chords?
Lattice boom chords are primarily affected by surface corrosion, pitting corrosion, and crevice corrosion. Surface corrosion is the most visible form and develops when protective coatings break down and expose the steel to moisture and oxygen. Pitting corrosion is more dangerous because it penetrates the material in localized areas, reducing wall thickness without being immediately obvious during routine visual checks.
Crevice corrosion tends to develop in the joints and connection points between chord members and lacing tubes, where moisture becomes trapped and accelerates oxidation. In offshore and coastal environments, saltwater accelerates all three types significantly. Left untreated, even surface corrosion can progress into pitting, and pitting can eventually cause through-wall penetration in thinner chord sections.
For crane operators working in humid, marine, or chemically aggressive environments, early identification of the corrosion type matters. Pitting and crevice damage in load-bearing chord sections require professional assessment before any repair decision is made, because the depth and distribution of material loss directly determine whether welding is viable.
Can corroded lattice boom chords be repaired by welding?
Yes, corroded lattice boom chords can be repaired by welding in most cases where the base material retains sufficient structural integrity. The key condition is that the steel must still be weldable at the repair site, meaning the corrosion has not caused through-wall failure across a critical cross-section or introduced cracking that extends into undamaged material.
The repair process typically involves removing all corroded material by grinding or cutting, then building up the section using certified filler materials that match the mechanical properties of the parent steel. For high-strength lattice boom steel, this requires careful heat management to avoid altering the microstructure of the surrounding material and introducing heat-affected zone weaknesses.
When corrosion damage is too extensive for weld repair alone, a partial chord replacement may be required. This involves removing the damaged section and welding in a new piece of matching material under full procedural control. In either case, the repair must be treated as a structural weld, not a cosmetic fix, and must meet the same quality standards as the original fabrication.
What welding procedures are used to repair high-grade lattice boom steel?
Repairing high-grade lattice boom steel requires a formally documented Welding Procedure Specification (WPS) tailored to the specific steel grade, material thickness, and repair geometry. For lattice booms manufactured from steels in the 690 to 1100 N/mm² range, standard welding procedures used for structural steel are not sufficient. The high yield strength of these materials demands precise preheat temperatures, controlled interpass temperatures, and compatible filler metals.
Welding Procedure Specification (WPS)
A WPS defines every variable that affects weld quality, including the welding process, electrode type, preheat and interpass temperature ranges, heat input limits, and post-weld requirements. For crane boom repairs, the WPS must be qualified and tested before it is applied to a structural component. This is not a document that can be improvised on-site. Reputable repair specialists prepare a WPS specific to each repair job before any welding begins.
Non-destructive testing after welding
Once welding is complete, all new welds on a lattice boom chord repair must undergo non-destructive testing (NDT). A 100% visual inspection is standard, followed by Magnetic Particle Inspection (MPI) to detect surface and near-surface cracks or inclusions. For critical repairs or when required by the certifying body, ultrasonic testing or radiographic (X-ray) testing may be performed by a third-party Notified Body to verify internal weld quality. No repaired lattice boom should return to service without passing these checks.
What happens to CE certification after a lattice boom is repaired?
CE certification for the crane remains valid after a lattice boom repair, provided the repair is carried out by a qualified specialist following documented procedures and verified through appropriate non-destructive testing. The repair must meet the standards of the original equipment, and the work must be traceable through documentation that can be presented during future inspections.
This is a critical point for compliance-focused operators. An improperly executed repair, or one carried out without a qualified WPS and NDT verification, can invalidate the crane’s certification and create serious liability exposure. Conversely, a properly documented repair performed by a certified specialist preserves the crane’s legal operating status and supports ongoing regulatory compliance.
Fleet managers and HSE officers should request full documentation from any repair provider, including the WPS, repair plan, NDT records, and a formal repair certificate. This paperwork is not an administrative formality. It is the evidence that the repaired crane meets its original performance specification and can legally return to lifting operations.
Is repairing a corroded lattice boom cheaper than replacing it?
In the majority of cases, repairing a corroded lattice boom chord is significantly cheaper than sourcing a replacement boom or boom section from the original manufacturer. OEM replacement parts for lattice booms involve long lead times, high procurement costs, and in some cases limited availability for older or less common crane models. A skilled repair returns the boom to full operational value at a fraction of that cost.
The cost advantage of crane boom repair extends beyond the part price itself. Every day a crane sits out of service waiting for a new boom section is a day of lost productivity. Emergency repairs carried out on-site or in a specialist workshop can restore the boom to service far faster than waiting for a manufactured replacement to be delivered, particularly for cranes operating in remote or international locations.
The decision to repair rather than replace is not always straightforward. Extensive corrosion across multiple chord members, or damage combined with fatigue cracking, may shift the cost-benefit calculation. A qualified inspection is the only reliable way to determine whether repair is the most economical path, which is why a thorough assessment should always precede any cost comparison.
How can lattice boom corrosion be prevented long-term?
Long-term prevention of lattice boom corrosion relies on a combination of protective coating maintenance, regular inspection, and controlled storage conditions. No single measure is sufficient on its own, but a structured maintenance programme significantly reduces the rate of corrosion development and extends the service life of the boom.
- Coating integrity: Inspect paint and protective coatings at regular intervals. Chips, scratches, and areas of coating failure should be touched up promptly before bare steel is exposed to moisture.
- Drainage and drying: Ensure that joints, connection points, and horizontal surfaces do not retain standing water. Trapped moisture accelerates crevice corrosion in areas that are difficult to inspect visually.
- Periodic professional inspection: Visual checks by operators are valuable, but they do not replace a thorough inspection by a qualified technician who can identify early-stage pitting or coating breakdown in hard-to-reach areas of the boom structure.
- Storage environment: When a lattice boom is stored for extended periods, covered or indoor storage reduces exposure to rain, humidity, and airborne contaminants. In coastal or offshore environments, additional corrosion inhibitor treatments may be warranted.
- Maintenance contracts: Scheduled maintenance agreements with a specialist provider ensure that inspections happen consistently rather than reactively, catching minor corrosion before it progresses to a point where structural welding is required.
Prevention is always more cost-effective than repair. A corroded chord that is caught at the surface stage can be treated with minimal intervention. The same chord left unattended for another season may require full structural weld repair or section replacement. For operators running multiple cranes or working in aggressive environments, a proactive maintenance programme delivers measurable savings over time.
How Rusch Cranes approaches lattice boom corrosion repair
Rusch Cranes is one of just three companies in Europe able to repair crane booms manufactured from 960 and 1100 grade high-strength steel, which makes them one of the few providers capable of handling the most demanding lattice boom chord repairs. Their approach to every repair covers the full process from initial assessment to certified completion:
- Material strength verification and preparation of a job-specific Welding Procedure Specification (WPS) and Repair Plan before any welding begins
- Precise measurement and photographic documentation of all damage prior to repair
- 100% visual inspection and 100% MPI on all new welds upon completion
- Third-party Notified Body involvement for ultrasonic or X-ray testing where required
- A 1-year guarantee on all performed repairs, with CE certification remaining valid after completion
- Worldwide service deployment, with repairs carried out at the client’s location or at the Rusch workshop in Medemblik, Netherlands, depending on which is most practical
If you have a lattice boom showing signs of corrosion damage and need a qualified assessment, contact Rusch Cranes to discuss your situation and find out whether welding repair is the right solution for your crane.
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