What impacts will weld defects have on the safety of building structures

The weld defects of stainless steel welded pipes have a significant impact on the safety of building structures, mainly in terms of strength, sealing performance, corrosion resistance, and fatigue resistance. The specific effects are as follows:

Strength reduction

Reduced load-bearing capacity: The weld is a critical part of the connection of stainless steel welded pipes. If there are defects such as pores, slag inclusions, or incomplete penetration, the effective bearing area of the weld will be reduced. When the building structure is subjected to loads, these defect areas are prone to form stress concentration, causing the weld to develop cracks prematurely and expand, thereby reducing the load-bearing capacity of the entire welded pipe and the building structure, and affecting the safety of the building.

Structural stability affected: Stainless steel welded pipes in building structures usually play a supporting and anchoring role. Weld defect may cause the welded pipe to undergo local deformation or fracture under force, destroying the overall stability of the structure, making the building more prone to severe accidents such as tilting and collapse when subjected to external forces such as earthquakes and wind loads.

Sealing failure

Leakage problem: For stainless steel welded pipes used in building water supply and drainage, gas systems, etc., weld defects such as incomplete fusion and cracks will damage the sealing performance of the weld. This may cause leakage of water, gas, etc. inside the pipe, not only resulting in waste of resources and environmental pollution, but also causing electrical short circuits, gas explosions, etc., endangering the lives and property safety of people.

Affecting the operation of related equipment: In some building systems that require a sealed environment, such as air conditioning systems, fire protection systems, etc., the sealing performance of the welded pipe is crucial. Weld defect-induced leakage will cause instability in system pressure, affecting the normal operation of the equipment, reducing the reliability and effectiveness of the system, and in emergency situations (such as fire when the fire protection system cannot supply water normally), may cause serious consequences.

Corrosion resistance weakened

Accelerated corrosion: The corrosion resistance of stainless steel welded pipes is an important performance to ensure their long-term use in buildings. Cracks, pores, etc. at the weld will destroy the passivation film on the surface of stainless steel, exposing the internal metal to the corrosive media such as air, moisture, acids, and alkalis, thereby accelerating the corrosion process at the weld.

Shortened service life: With the intensification of corrosion, the strength and sealing performance of the weld will further decline, leading to premature failure of the welded pipe and the need for replacement or maintenance. This not only increases the maintenance cost of the building but also may affect the normal use of the building during maintenance.

Fatigue performance damaged

Fatigue crack expansion: During the use of buildings, stainless steel welded pipes may be subjected to periodic load effects, such as building vibration, thermal expansion and contraction. Weld defects will become the starting point of fatigue cracks, and under the cyclic load action, the cracks will continue to expand, eventually causing fatigue fracture of the welded pipe.

Increased risk of sudden accidents: Fatigue fracture usually occurs without obvious warning and has great suddenness and danger. When the weld of the stainless steel welded pipe fails due to damaged fatigue performance, it may suddenly disrupt the force balance of the building structure, causing local or overall structural damage, and posing a serious threat to the lives and facilities of people inside the building.