Рэзюмэ
Corrosion is a progressive, often hidden degradation process that reduces a material’s effective load-bearing area, alters its microstructure and produces stress concentrators — all of which directly reduce tensile strength and ductility.
In typical practical scenarios, corrosion can lower tensile strength by ~30–50% and cut ductility indicators (падаўжэнне, reduction of area) па ~40% or more, transforming tough, deformable components into brittle, sudden-failure risks.
The consequence is not only material loss but cascading system failures, safety incidents and major economic impact.
Understanding the mechanisms, measuring performance loss, and implementing a layered prevention and monitoring program are essential to protect structures and machinery.
1. Core Mechanisms: How Corrosion Undermines the Mechanical Fundamentals of Materials
The degradation of tensile strength and ductility by corrosion is not a superficial phenomenon but a multi-faceted process that erodes material performance at both the macroscopic and microscopic levels.
The damage is irreversible, and its impact on mechanical properties is driven by three primary, interrelated mechanisms, each targeting a critical aspect of material structural integrity.
Reduction of Effective Load-Bearing Area Induces a Sharp Drop in Tensile Strength
Corrosion attacks material surfaces and even internal matrices, forming loose rust layers, deep pitting cavities, and corrosive pores that directly reduce the effective load-bearing area of the material— the actual cross-sectional area capable of withstanding external tensile stress.
For common engineering materials such as carbon steel, Алюмініевыя сплавы, and low-alloy steel, severe corrosion can reduce the effective load-bearing area by 30% да 50%.
Under the same applied load, the reduction in load-bearing area leads to significant stress concentration at corrosion defects, where the actual stress borne by the material far exceeds the design stress.
This concentration effect directly weakens the material’s tensile strength: corroded structural steels typically experience a 30% да 50% reduction in ultimate tensile strength (Ots),
rendering materials that once met design load requirements unable to withstand even normal operational stresses, and increasing the risk of sudden tensile fracture under service conditions.
Microstructural Damage Eliminates Ductility, Causing Embrittlement and Brittle Fracture
Corrosive media—including acids, шчолачы, chloride ions, сульфіды, and hydrogen ions—penetrate the material’s internal microstructure through surface defects, disrupting the atomic bonding forces between grains and along grain boundaries.
This triggers a series of harmful microstructural changes, such as intergranular corrosion, каразійнае парэпанне пад напругай (SCC), вадародная далікатнасць, and intermetallic compound precipitation, all of which destroy the material’s plastic deformation capacity.
Пластычнасць, characterized by indicators such as elongation after fracture і reduction of area, is the material’s ability to undergo plastic deformation before fracture—a key property that prevents sudden brittle failure.
Corrosion-induced microstructural damage causes these ductility indicators to decline by more than 40% for most engineering materials: tough metals that originally exhibited plastic bending and deformation under stress lose this ability and become highly brittle.
Instead of undergoing gradual plastic deformation, corroded materials fracture abruptly under tensile load, eliminating the early warning signs of failure and drastically increasing the risk of unanticipated structural collapse.
Corrosion Type Determines the Focus of Mechanical Property Degradation
Corrosion manifests in multiple forms, each with distinct damage characteristics and targeting different mechanical properties of materials.
The three most common corrosion types in engineering applications exhibit divergent impacts on tensile strength and ductility, as outlined below:
- Uniform Corrosion: This form of corrosion attacks the entire material surface evenly, causing gradual thinning of the matrix.
Its primary effect is a steady, linear reduction in the effective load-bearing area, leading to a slow but consistent decline in tensile strength.
While uniform corrosion is relatively easy to detect and predict, prolonged exposure still results in severe tensile strength loss and eventual structural failure. - Localized Corrosion: Including pitting corrosion, карозія шчыліны, and filiform corrosion, this type of corrosion concentrates on small, discrete areas of the material surface, forming deep pits or narrow corrosive gaps.
These defects act as critical stress concentration points, not only accelerating the reduction in local tensile strength but also severely damaging ductility by creating pre-cracked zones.
Localized corrosion also drastically shortens the material’s fatigue life, making it prone to fracture under cyclic tensile loads even at stress levels far below the material’s ultimate tensile strength. - Стрэс -трэсканне карозіі (SCC): This is the most lethal form of corrosion for structural materials, occurring under the combined action of напружанне расцяжэння (residual or operational) and a corrosive medium.
SCC initiates microcracks at the material’s surface or interior, which propagate rapidly under the dual drive of stress and corrosion, without significant plastic deformation.
This rapid crack growth leads to a sudden, catastrophic drop in both tensile strength and ductility, causing brittle fracture of materials that would otherwise exhibit good ductility—even at ambient temperatures and normal operational stresses.
SCC is the primary cause of unexpected failure in pressure vessels, трубаправоды, і аэракасмічныя кампаненты, and its damage is often irreversible and difficult to detect in advance.
2. Industrial Hazards: The Cascade of Failures from Corrosion-Induced Mechanical Property Degradation
The erosion of tensile strength and ductility by corrosion has become an unignorable “invisible hidden danger” across all industrial sectors, leading to direct and indirect economic losses on a global scale, as well as severe safety accidents that threaten human life.
The far-reaching impacts of corrosion-induced mechanical property degradation in key industries are detailed below:
Manufacturing Industry: Production Downtime and Component Failure
In mechanical manufacturing, прэцызійныя дэталі, формы, and structural components rely on stable tensile strength and ductility to ensure operational accuracy and load-bearing capacity.
Corrosion-induced tensile strength loss causes components such as gears, шахты, and connecting rods to fracture or deform under operational loads, leading to unplanned production line downtime.
For medium and large manufacturing enterprises, the daily economic loss from a single production line shutdown due to corroded components can reach tens of thousands of US dollars.
Дадаткова, the brittlement of corroded molds reduces their plastic forming capacity, leading to defective products and further increasing production costs.
Energy and Chemical Industry: Leaks, Explosions, and Process Disruptions
Трубаправоды, пад ціскам, цеплаабменнікі, and storage tanks in the energy and chemical industry operate in harsh environments with high temperatures, высокі ціск, and aggressive corrosive media (e.g., acidic crude oil, chemical solvents, and high-chloride brines).
Corrosion weakens the tensile strength and ductility of these critical structures: a reduction in tensile strength makes them unable to withstand internal pressure, while ductility loss eliminates their ability to absorb pressure fluctuations through plastic deformation.
This combination often leads to media leakage, and in severe cases, catastrophic explosions and fires.
Such incidents not only result in the loss of valuable raw materials and production downtime but also cause environmental pollution and serious casualties, with single-accident losses often exceeding millions or even hundreds of millions of US dollars.
Transportation Industry: Structural Fracture and Threats to Passenger Safety
The transportation sector—including automotive, марская, чыгунка, and aerospace—relies on structural materials with reliable tensile strength and ductility to withstand dynamic and cyclic loads during operation.
Automotive chassis and suspension components corroded by road salt and moisture experience reduced tensile strength, leading to structural fracture during driving;
marine ship hulls and offshore platform structures exposed to seawater suffer from pitting and crevice corrosion, which impairs ductility and causes brittle fracture of hull plates under wave loads;
railway track components and bridge structures corroded by atmospheric pollutants lose their load-bearing capacity, threatening the safety of train operations.
In all these cases, corrosion-induced degradation of mechanical properties directly endangers the safety of passengers and crew, and the resulting accident rescue and post-disaster reconstruction costs are enormous.
Будаўніцтва і інфраструктура: Structural Instability and Excessive Maintenance Costs
Steel structure bridges, factory frames, high-rise building supports, and municipal infrastructure (e.g., water supply and drainage pipelines) are exposed to atmospheric corrosion, rainwater erosion, and soil corrosion for long periods.
Corrosion causes a year-by-year attenuation of the tensile strength and ductility of steel structures: uniform corrosion thins steel beams and columns, reducing their tensile load-bearing capacity, while intergranular corrosion weakens the bonding between grains, leading to brittle fracture of structural components.
З цягам часу, this degradation leads to structural instability, requiring costly maintenance and reinforcement.
For aging infrastructure, the cost of replacing corroded structural components can account for 30% да 50% of the total construction cost of the project.
In extreme cases, severe corrosion even leads to bridge collapse and building structural failure, causing immeasurable social and economic losses.
Аэракасмічная прамысловасць: Precision Failure and Risks to Flight Safety
Aerospace components operate in extreme environments, including high-altitude atmospheric corrosion, fuel erosion, і цыклічны тэрмічны стрэс, and their mechanical properties—especially tensile strength and ductility—are subject to the strictest requirements.
Even minor corrosion damage to precision components such as aircraft engine blades, шасі, and satellite structural parts can lead to a significant decline in mechanical performance:
a small pitting defect can cause stress concentration and trigger fatigue fracture under high-speed operation, while stress corrosion cracking can lead to sudden component failure during flight.
The failure of aerospace components due to corrosion not only results in the loss of expensive equipment but also poses a direct threat to the safety of pilots and astronauts, with far-reaching consequences for aerospace missions and national security.
3. Comprehensive Anti-Corrosion Strategies: Four Core Measures to Preserve Material Mechanical Properties
Mitigating the degradation of tensile strength and ductility by corrosion requires a full-life-cycle approach that spans source prevention, кантроль працэсу, and post-operation monitoring and maintenance.
A comprehensive anti-corrosion system must be established to isolate corrosive media, аптымізаваць выбар матэрыялу, and monitor performance changes in real time, thereby safeguarding the mechanical properties of materials and ensuring the long-term stable operation of equipment and structures.
The four core protective measures are detailed below:
Precision Material Selection: Address Corrosion Risks at the Source
Material selection is the most fundamental and cost-effective anti-corrosion measure, which requires matching the material’s corrosion resistance to the specific service conditions—including corrosive medium type, канцэнтрацыя, тэмпература, ціск, and humidity.
For different corrosive environments, targeted material selection principles should be adopted:
- In chemical production environments with strong acids, шчолачы, or oxidizing media, select high-corrosion-resistance alloys such as 316L з нержавеючай сталі, Hastelloy C-276, і тытанавыя сплавы, which form a dense, self-healing passive film on the surface to resist medium penetration.
- In marine and offshore environments with high chloride ion concentrations, use seawater-resistant steels (e.g., AH36 marine steel) or duplex stainless steels (e.g., 2205, 2507), which exhibit excellent resistance to pitting and crevice corrosion.
- In mild atmospheric corrosion environments (e.g., indoor industrial workshops, residential buildings), use cost-effective anti-corrosion coated steels (e.g., ацынкаваная сталь, painted steel) to balance corrosion protection and economic efficiency.
By selecting the right material for the right application, the risk of corrosion-induced mechanical property degradation is minimized from the design stage, laying a solid foundation for structural safety.
Павярхоўная абарона: Form a Dense Barrier to Isolate Corrosive Media
Surface protection technologies create a physical or chemical barrier on the material surface, isolating the metal matrix from corrosive media and preventing or delaying the onset of corrosion.
This is the most widely used anti-corrosion measure in engineering, with a variety of mature technologies suitable for different materials and application scenarios:
- Organic Coating: Apply anticorrosive paint, epoxy resin coating, or polytetrafluoroethylene (Ptfe) coating to the material surface to form a flexible, dense organic film.
This technology is low-cost and easy to implement, and is widely used for steel structures, трубаправоды, and mechanical components. - Electroplating and Hot Dipping: Use electroplating (цынкаванне, храмаванне, нікеліраванне) or hot dipping (hot-dip galvanizing, hot-dip aluminizing) to form a metallic protective layer on the material surface.
The protective layer either acts as a sacrificial anode (e.g., цынк) to corrode itself and protect the base metal, or forms a passive film (e.g., хром) to resist medium erosion. - Chemical Passivation: Treat stainless steel, Алюмініевыя сплавы, and other metals with passivators (e.g., азотная кіслата, chromate-free passivators) to form a thin, dense chemical passive film on the surface, enhancing the material’s inherent corrosion resistance.
- Тэрмічнае напыленне: Spray molten metal (e.g., цынк, алюміній) or ceramic materials onto the material surface at high temperature to form a thick, Устойлівы да зносу, and corrosion-resistant coating.
This technology is suitable for heavy-duty corrosion environments such as marine platforms and industrial pipelines.
Environmental Optimization: Control Corrosive Factors to Reduce Erosion
Optimizing the service environment of materials and structures by reducing or eliminating corrosive factors is an effective supplementary measure to material selection and surface protection.
This measure targets the root cause of corrosion and is particularly suitable for industrial production sites and fixed infrastructure:
- In industrial workshops, install waste gas treatment equipment to remove acidic, alkaline, and sulfide-containing exhaust gases, and use dehumidification systems to control ambient humidity below 60%, reducing atmospheric corrosion.
- In marine and offshore environments, add corrosion inhibitors to cooling water and seawater contact systems to slow down the corrosion rate of materials,
and perform regular fresh water flushing on structural surfaces to remove salt deposits and chloride ions. - In chemical production processes, purify the process medium to reduce the content of corrosive impurities (e.g., chloride ions, сульфіды), and use inert gas protection for key equipment to isolate corrosive media and oxygen.
- In soil environments, use anti-corrosion wrapping materials for buried pipelines and replace corrosive soil with neutral backfill soil to reduce soil corrosion.
Regular Monitoring and Maintenance: Detect Defects Early and Avoid “Operation with Defects”
Corrosion is a progressive process, and regular monitoring and timely maintenance can detect early corrosion damage, evaluate the degree of mechanical property degradation,
and take corrective measures before failure occurs—avoiding the risks of “operation with defects” and sudden structural failure.
A scientific monitoring and maintenance system includes the following key steps:
- Неразбуральнае тэставанне (Ndt): Use ultrasonic testing (UT) to measure the thickness of corroded materials and evaluate the reduction in effective load-bearing area;
use liquid penetrant testing (Pt) and magnetic particle testing (Гол) to detect surface and near-surface corrosion cracks and pitting defects; use eddy current testing (ET) for non-destructive testing of non-ferrous metal components.
NDT enables non-invasive evaluation of corrosion damage and mechanical property degradation, providing a scientific basis for maintenance decisions. - Continuous Corrosion Monitoring: Install online corrosion monitoring equipment (e.g., corrosion coupons,
electrochemical corrosion sensors) on key equipment and structures to monitor the corrosion rate in real time and issue early warnings when the corrosion rate exceeds the safe threshold. - Establish Maintenance Records: Set up a detailed equipment maintenance ledger to record the corrosion status, testing results, and maintenance measures of each component, tracking the changes in material mechanical properties over the service life.
- Timely Replacement and Reinforcement: For components with severe corrosion and significant mechanical property degradation (e.g., tensile strength reduced by more than 30%),
replace them in a timely manner; for partially corroded structural components, use reinforcement measures such as adding stiffeners and wrapping anti-corrosion layers to restore their load-bearing capacity.
4. Высновы
Corrosion is not merely a surface cosmetic issue — it is a structural hazard that degrades tensile strength, erodes ductility and converts ductile failures into brittle, sudden fractures.
Quantitatively, moderate to severe corrosion commonly reduces tensile strength by tens of percent and cuts ductility measures by similar or larger fractions; fatigue life and residual service life can collapse catastrophically due to localized attacks.
The only reliable defense is an integrated program of correct material selection, engineered protection, environment control, routine inspection and timely maintenance or replacement.
For safety-critical systems, conservative design margins, frequent monitoring and documented fitness-for-service assessments are indispensable.
