1. Can a leaking steel pipe be welded directly?

The answer is: Yes, but there are strict conditions and risks involved, and it's generally not recommended as a first-line method, especially for leaking pipes.

Risks and Difficulty:

Water Flow Removes Heat: Welding requires high temperatures to melt the metal. Leaking water continuously removes heat, causing the weld temperature to fall below the required level, making it difficult to form a solid weld pool and making the weld very likely to fail.
Porosity and Defects: Water rapidly vaporizes at high temperatures, producing water vapor. Water vapor trapped in molten metal can cause weld defects such as pores and slag inclusions, which in turn become new leaks.
Significant Safety Hazards: Water conducts electricity, which can easily cause the welding machine to short-circuit during welding, posing an electric shock risk to the operator. Furthermore, in confined spaces, the sudden expansion of water vapor can also be dangerous.
Risk of Leakage Expansion: If handled improperly, the thermal stress of welding can even exacerbate existing cracks.

When is welding permitted? If the leak is only a very small one (e.g., the size of a pinhole), or if the pipeline has been completely shut down, drained, thoroughly dried, and ventilated to ensure there are no flammable or explosive gases inside, then welding repairs can be performed by highly experienced professional welders using specialized techniques (such as arc welding, root pass welding, or underwater welding). However, this is a highly skilled operation.

2. Common Steel Pipe Leak Repair Methods

For pressurized or slightly depressurized pipelines, the more common modern method is non-hot work, which includes the following:

Method 1: Using Pipe Repair Clamps (Pipe Repairers)

This is currently the most popular, quickest, and most efficient repair method. Its advantages are detailed below.

Method 2: Using Clamps (Steel Banding for Sealing)

Suitable for small leaks in straight pipe sections with low pressure.

Operation: Use a metal clamp containing a rubber gasket directly around the leak. Tighten the bolts and compress the rubber gasket to achieve a seal.

Advantages: Low cost and quick installation. Disadvantages: They generally lack the pressure-bearing capacity of pipe repair clamps and are less effective at sealing irregular surfaces or welds.

Method 3: Injection-Based Pressure Sealing

Suitable for leaks in complex locations (such as flanges, valves, and welds).

Operation: First, install a specialized clamp at the leak site. Then, inject a specialized sealant through the clamp's injection hole. The sealant cures within the cavity, forming a new sealant layer.

Advantages: Widely applicable, flameless, and can be used in-line.

Disadvantages: Requires specialized personnel and equipment, resulting in high costs and relatively complex installation.

Method 4: Cold Welding (Sealing Stick/Emergency Repair Agent)

Suitable for static pinholes and small holes in low-pressure or vacuum environments.

Operation: A two-component polymer material, similar to putty, is manually mixed and applied directly to the leak site. It quickly cures and adheres to the metal, sealing the leak.

Advantages: Very simple and extremely low cost.

Disadvantages: Poor pressure and impact resistance, usually used as a temporary emergency measure.

3. Advantages of Using Pipe Repair Clamps

Pipe repair clamps are a highly advantageous option for modern pipeline repairs, especially for common medium and low-pressure pipelines.

1. Efficient and Fast, No Production Downtime:
The biggest advantage is that they can usually be operated under pressure, eliminating the need to drain the pipeline or shut down the system, significantly reducing the economic losses caused by downtime.
2. Safe and Reliable, No Hot Work:
The entire installation process is purely mechanical, requiring no hot work welding, completely eliminating safety hazards such as fire, explosion, and electric shock. They are particularly suitable for flammable and explosive environments such as the petroleum, chemical, and gas industries.
3. Excellent Sealing Performance:
Utilizing a high-strength metal shell (such as carbon steel or stainless steel) and an internal, high-quality elastic sealing strip (such as NBR or EPDM rubber), bolted together, they generate a high sealing pressure ratio, capable of withstanding high pipeline pressures.
The design is typically fully enclosed, completely enclosing the leak point and surrounding weak areas, strengthening the overall structure and achieving greater effectiveness than simply plugging a single point.
4. Wide Adaptability:
The corresponding pipe repair clamp model can be selected based on the pipe specifications (diameter and wall thickness), providing high versatility. In addition to repairing straight pipes, there are also pipe repair clamps (flange spreaders) specifically designed to repair flange leaks.

The surface preparation requirements for these pipes are relatively minimal; only loose rust and debris need to be cleaned.

5. Simple Installation and Cost-Effectiveness:

Operation is simple, allowing ordinary repair personnel to operate with minimal training, eliminating the need for expensive professional welders.

While the cost of a single pipe repair clamp may be higher than the welding materials, the overall cost-effectiveness is generally optimal when considering downtime costs, safety risks, labor skill requirements, and installation speed.

6. Permanent Repair Capability:

High-quality pipe repair clamps are designed and designed to last the remaining service life of the pipe, making them a permanent repair solution, not just a temporary measure.

The housing is typically made of metals such as ductile iron and carbon steel, which are corrosion-resistant and high-strength. It can last the same life as the original pipe, eliminating the need for frequent repairs. Baoshuo brand carbon steel half joints are available in a variety of rubber materials, including NBR, EPDM, FKM, and silicone rubber. The half joint body is available in Q235 carbon steel and 304 and 316L stainless steel.

The following are Baoshuo brand oil-resistant pipe repair clamps, high-temperature-resistant pipe repair clamps, acid- and alkali-resistant pipe repair clamps, stainless steel pipe repair clamps, high-pressure-resistant pipe repair clamps, and large-diameter pipe repair clamps.

Summary and Recommendations

Emergency Procedures: If a leak occurs, first assess the leak volume and pressure. If the pressure is low, you can temporarily stop the leak with a plugging rod or clamp.
Permanent Repair: For permanent repairs, pipe repair clamps are the best option in most cases because they are safe, quick, reliable, and economical.
Welding Repair: Welding repair is only recommended as a backup option by a professional welder when the pipe can be completely drained, dry, and safe to use hot metal.
Professional Judgment: If the pipe pressure is very high, the pipe diameter is very large, or the leak is complex, it is recommended to contact a professional pipe repair company for on-site inspection and treatment.