How to Test if There is Internal Corrosion of Stainless Steel Pipe Fittings

    

Two Methods to Test the Internal Corrosion of Pipe Fittings

For all kinds of stainless steel pipe and fittings, internal corrosion is a very common phenomenon. When the its inside corroded, the wall thickness of pipe fittings will become thinner, and steel pits and spot will appear in the surface, which will affect the service life of the fittings and bring safety concerns.

Currently, the most widely used test methods for stainless-steel pipe fittings are magnetic flux leakage and ultrasonic testing.

Ultrasonic Testing

The principle of ultrasonic testing is to measure the wall thickness of pipe through ultrasonic pulse reflection. When testing, the probe will send ultrasonic pulse to the wall. Next, after probe received the reflection pulse from inner surface and outer surface of the tube, the thickness of tube wall then can be calculated.

Magnetic Flux Leakage Testing

The principle of magnetic flux leakage testing is based on the high permeability of ferromagnetic materials. After stainless-steel pipe fittings get corroded, the permeability at the corrosion part will be far less than other parts. And after pipe fittings being magnetized:

The magnetic lines will be even if there are no defects inside the pipe fittings;

The magnetic lines will bend, and surpass the surface of the pipe if there are defects inside the pipe fittings.

The defect can be determined by detecting the flux leakage from the magnetized surface.

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Venezuela Oil Export to China Reaches 1130 Barrels in 2020

   

Why will Venezuela Oil Export to China under America's prohibition?

For major economies, oil is an important strategic resource, and plays an important role in industrial development. It once has been called "the blood of industry". When speaking of oil, most of us will come up with Saudi Arabia, because there are many oil tycoons in this country, and rich in oil resources reserves has created great wealth for the local. 

In fact, Saudi Arabia is not the country with the largest oil reserves, but Venezuela is. According to the related statistics, the Venezuela oil explort have reached 296 billion barrels, which is the country with largest oil reserves.

Venezuela had earned great profits through selling oil to other countries. However, it did not last for a long period of time. Under the sanctions of the United States, Venezuela's oil export industry was greatly impacted, and even fell into a standstill situation for a time.

In 2019, United States announced to impose sanctions on Venezuela oil companies. After that, Venezuela has seen an exodus of oil buyers. The report on 22^nd January showed that Venezuela's oil exporters exported at least 11.3 million barrels of oil to China in 2020 with the help of a Swiss oil trading companies.

It may puzzle many of us that since Venezuela can export oil through changing the export destination, then China certainly will not be its only choice. Why is Venezuela willing to export oil to China, and making its volume exceeds 10 million barrels?

Regarding on this, there are two factors.

First one is that China has always been the country with the largest oil demands. In the year of 2020, China is the first country to recover the economic activities under the pandemic situation. Thus, China’s strong demands on oil has become the key to revive Venezuela’s oil exports.

Related statistic shows that China imported crude oil worthy of $163.8 billion in first 11 months of 2020. Currently, the energy demand in a lot of countries remain flagging, and China now becomes a “life saver” for Venezuela's oil exporters.

Second one is that the oil export for Venezuela is facing unprecedented crisis under the sanctions of the United States, even though it has the largest oil reserves. Besides, due to bad governance and health events, Venezuela’s position in global oil market has been greatly diminished.

Now, for oil traders in Venezuela, their main task is to explore international market to recover the market shares. Or it will be useless even if the oil reserves are rich.

It needs to know that China is on Venezuela's side in the "oil dispute" between the United States and Venezuela. In past, China claimed objection towards America’s restriction for Venezuelan oil. Besides, China supports Venezuela to export oil to China. And China says it will take necessary measures to protect the legitimate rights and interests of its companies and ensure the normal operation of legitimate trade activities between China and Venezuela.

Posted by KAYSUNS, the stainless steel pipe and fittings supplier.

Sealing Of Vacuum Valves

   

Sealing (Air Tightness)is a very important point for vaccum valves

Sealing of vacuum valves is one of important requirements. only when sealing meets the requirements, the product works.

As a product used under vacuum conditions, the vacuum valve not only has standard accuracy in the positioning of the basic functions of the cut-off, but also can effectively serve the needs of vacuum environment management while realizing an effective cut-off function guarantee.

To ensure the performance of good management functions, the practical application of vacuum valve products has very important professional requirements. More importantly, it is necessary to ensure that there are good functional standards to achieve the purpose of good service practices. Service standards, as a professional tool with strong practicability, vacuum valves need to achieve good advantages in ensuring that they have good valve guarantee characteristics, actual functions and product quality. 2 important points of sealing of vaccum valves and convenient operation.

Sealing Of Vacuum Valves: As a shut-off valve used in a vacuum environment, the sealing of vacuum valves is a condition. Only by accurately achieving a reasonable seal can the management of the air flow and the effective purpose be achieved.

The service standards are based on professionalism. It is also the basic principle and characteristic of the service that can improve the standard and reasonable. Only when the basic conditions of sealing are truly met, can it be used in actual production and have a good function. It is also an important quality standard for actual production and application.

Easy to operate: the pressure that needs to be endured can play a good role in practical production.

At this time, for the majority of consumers, it is necessary to ensure the good function and application of the valve. In fact, the use of vacuum environment requires it play a stable role at any time.

The norms and requirements of the operation play a decisive role in the practical application, and it is a suitable choice to achieve a good improvement in functions, and it is a required quality standard.

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Posted by KAYSUNS, stainless steel pipe fittings supplier.

The Latest Competitiveness Ranking Of Chinese Steel Companies Released, Baowu Steel Group Reached The World-class Steel Company

   

Baowu Steel Group Becomes The Top Steel In The World

The Finance Association News on December 21st, the "Evaluation of the Development Quality (and Comprehensive Competitiveness) of Iron and Steel Enterprises" (2020) issued by the Metallurgical Industry Planning and Research Institute on the 21st showed that the Mittal and other world iron and steel companies conducted a comparative analysis. The development quality (and comprehensive competitiveness) of China Baowu Group ranks first in the global steel industry and has reached the world's super-class.

Baowu Steel Group

In addition, Shougang, CITIC Pacific Special Steel, Shagang, Hegang, AnSteel Group, and Shangang Group have reached world-class levels.

This is the 10th consecutive year that the institution has researched and released the competitiveness ranking of stainless steel pipe fittings companies.

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In accordance with the requirements of “building a world-class enterprise with global competitiveness”, 12 indicators including scale, profitability, efficiency, environment, innovation, and market are selected, and the development quality (and comprehensive competitiveness) of this year is evaluated as A+ (extremely strong) 15 steel companies and the world's top steel companies such as South Korea's Pohang, Japan Steel, JFE, ArcelorMittal, etc. were compared and analyzed.

Based on comprehensive research and judgment, China Baowu Steel Group's development quality (and comprehensive competitiveness) ranks first in the global steel industry, reaching the world's super-class (A+);

The development quality (and comprehensive competitiveness) of Shougang Group, CITIC Pacific Special Steel, Shagang Group, Hegang Group, Angang Group, Shangang Group, Valin Iron and Steel Group, and Nangang Group has reached world-class (A);

The development quality (and comprehensive competitiveness) of Liugang Group, Jianlong Heavy Industry, Delong Steel, Rizhao Steel, Xinxing Casting Pipe, and Tsingshan Holding Group has reached the world's quasi-first-class (B+).

How Does Sanitary Clamp Works On The Pipeline

 

Classification And Technical Use Of Clamps

First of all, let's understand what a sanitary clamp is? Although this term doesn't work on pipes, it has a great effect; so far, many people still don't know what the clamp looks like. There are many sanitary clamps includes heavy duty single pin clamp, double pins clamp and safety clamps etc; here sanitary pipe fittings supplier - wellgreen will focus on how does clamp works on pipelines.

Sanitary stainless steel clamp

Sanitary clamps are also called hygienic clamps. Sanitary clamps are divided into hose clamps and hoops. What are hose clamps and hoops we will continue to talk about below; the main purpose of sanitary clamps is also named according to its name. The word sanitary is meant to be clean, clean and hygienic. Its use value is also very high, because sanitary clamps are basically used in food pipelines and medical pipelines.

Forming and technical parameters of sanitary on how does clamp works:

1. Sanitary clamps are formed by casting stainless steel and stamping stainless steel plates; the so-called casting means that stainless steel is melted into a liquid at a high temperature of 1550 degrees Celsius, and then poured into a refined silicon melt mold to slowly cool and form. This is only the blank molding of the clamp, not the finished product; there are also components that have undergone surface treatment (vibration) and perforation, rivet retention, ingot nut and other components. Vibration refers to the use of vibration technology to polish and must be hygienic Clean standard; this is a perfect quality product.

2. The application field of sanitary clamps is more common in food and medical pipelines. As mentioned above, I will explain in detail here; why the surface should be polished, because the docking equipment of food and medical pipelines must basically meet the national sanitary standards , Even its finish must have a certain standard. If the user has higher requirements on the product, the stainless steel and high nickel materials SUS304 and SUS316L are basically used; this kind of sanitary clamp is also used in chemical equipment and water treatment equipment.

3. The stainless steel stamping clamp is relatively simple, the manufacturing process is simpler; it is stamped and formed from a stainless steel plate, and then matched with the relevant components; the surface of the product can be polished or whitened according to the user.

4. The nominal pressure of sanitary clamps can be 0~4.0mpa, divided into low pressure clamps, normal pressure clamps and high pressure clamps.

5. Sanitary clamps currently available in the market have diameters ranging from DN15 to DN630; larger ones need to be customized.

The above is just a brief introduction to the molding and technical parameters of several clamps about how does clamp works.

Application Fields Of Duplex Stainless Steel Welded Pipe

 

Now with the continuous development of the chemical industry in China, the use of duplex stainless steel welded pipe is increasing. The global demand for duplex stainless steel pipes is growing rapidly every year, and there is also a good development in petroleum, urea and other industries.

The outstanding performance of duplex stainless steel pipes is mainly higher yield strength and better stress corrosion resistance, its welding performance is good, and the sensitivity of welding cold cracks and hot cracks is low.

Austenitic stainless steel welded pipes are mainly used in the decorative field, and relatively few corrosion-resistant welded pipes are used in the petrochemical field.

Chemical and petrochemical processing industry

The chemical industry is the area where duplex stainless steel is used earlier and more frequently. The catalyst tube of the medium and small methanol synthesis reactor uses duplex stainless steel, and the large and medium-sized device uses 2205 duplex stainless steel welded pipe.

Oil and gas industry

This is one of the main application aspects of duplex stainless steel. For the production of duplex stainless steel welded pipes for petroleum, the Chinese stainless steel pipe and fittings suppliers offer a good solution. It has done a good job in cost control, such as adopting new technologies and new processes, using molybdenum oxide balls instead of metal molybdenum, and nickel oxide instead of metal nickel, reducing smelting costs, popularizing the use of duplex stainless steel continuous casting technology, and increasing the yield.

Fertilizer Industry

The fertilizer industry mainly uses 0Cr25Ni6Mo3CuN aging-strengthened duplex stainless steel. Its wear and corrosion resistance is used for the internal parts of high-pressure shut-off valves of various specifications in the main process pipeline of the urea plant. The effect is still good.

The CO2 stripping method and NH3 stripping method for the production of urea mostly use high-alloy austenitic stainless steel, even titanium. The domestic has begun to use high-chromium duplex stainless steel instead of 316L on the carbamate pump body of the large-scale urea plant. (Urea grade) steel. Since the 1980s, the three high-pressure equipment of the stripping tower, the carbamate condenser and the high-pressure decomposition tower in the new ACES urea process developed by Japan’s Toyo Engineering Company have adopted DP-12 (25Cr-7Ni-3Mo containing trace tungsten and copper). -N steel) and R-5 (00Cr25Ni6.5Mo1.5N) duplex stainless steel. The former is used to make gas stripping pipes, condensers, decomposition pipes and conveying pipes, while the latter is used for high-pressure equipment shells.

Chemical Composition And Corrosion Resistance Of 2707HD Duplex Steel (s32707 Stainless Steel)

    

2707HD duplex steel is a super duplex stainless steel, and its corresponding UNS grade is S32707 stainless steel.

Special super duplex stainless steel is designed to solve the lack of local corrosion resistance and strength of super duplex stainless steel heat-resistant chloride. It came out after 2000. The PRE value of S32707 stainless steel can be as high as 49. It is high in nitrogen, molybdenum, chromium and duplex. The structure makes the yield strength and tensile strength of the steel pipe up to 800MPa and 1000MPa, respectively, and the plasticity and toughness are also maintained at a relatively high level required for engineering applications.

Heat exchanger

The advent of 2707HD duplex steel has greatly broadened the application range of duplex stainless steel and improved its competitiveness with high-nickel materials such as super austenitic stainless steel and high-nickel corrosion-resistant alloys in engineering applications. The structure of 2707HD duplex steel is not significantly different from super duplex stainless steel such as 2507 stainless steel.

Chemical composition of 2707HD duplex steel (%)
Chemical composition grade	UNS grade	C	Si	Mn	S	P	Cr	Ni	Mo	Cu	N
		max	max	max	max	max
00Cr27Ni7Mo5N	SAF 2707HD	0.03	1.00	1.50	0.02	0.035	26/29	5.5/9.5	4.0/5.0	1	0.3/0.5
	UNS S32707

Since the yield strength of general duplex stainless steel is twice that of general austenitic stainless steel, the use of duplex stainless steel can greatly reduce the thickness of the material and reduce the weight of the equipment, which can save materials and reduce costs. 2707HD duplex Steel is higher than general duplex stainless steel and super duplex stainless steel, and has the advantages of saving materials and reducing costs.

S32707 stainless steel has good weldability. It is mostly used for heat exchanger tubing. TIG/GTAW (tungsten inert gas/tungsten inert gas arc welding) welding is recommended for the welding of the steel pipe and tube sheet, or manual For welding and TIG automatic welding, the welding consumables can be Sandvik 27.9.5L. In the α+γ duplex structure of the weld metal and heat-affected zone, the content of ferrite is 30% to 70%.

For heat exchangers, it is recommended to use the TIG/GTAW method to weld the tube to the tube sheet. The thermal cycle must be strictly controlled during the welding process, the interlayer temperature is less than 100℃, and the heat input Q range is 0.2～1.5KJ/mm.

S32707 stainless steel has excellent resistance to pitting, crevice corrosion and stress corrosion in chloride environments, and is particularly suitable for manufacturing heat exchanger equipment that uses seawater and chloride ions as working and cooling media. For example, the top heat exchanger bundle of the atmospheric distillation unit of the refinery has replaced 2507 duplex stainless steel with S32707 stainless steel, and the seawater condenser cooling tube made of 2707HD (the tube side is connected to seawater) has achieved satisfactory results. Due to the chemical composition and performance characteristics of this steel, it will be expanded to be used in applications resistant to some inorganic and organic acids.

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Posted by stainless steel pipe fittings supplier, KAYSUNS