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malleable iron pipe fittings

Malleable iron pipe fittings offer shock and corrosion resistance as well as mechanical strength. Water can be transported using galvanized fittings galvanized with pure zinc. Because narrow threads seal pipes more tightly, they reduce leakage risk.

The advantages of Jianzhi Group's malleable iron pipe fittings

Good quality

Malleable pipe fittings used in gas systems are extremely safe because of the catastrophic consequences in the event of a leak. The malleable pipe fittings are produced by Jianzhi Group. Each pipe fitting will undergo a pressure test before leaving the factory. Only the pipe fittings that pass the test can be sold. In addition, Jianzhi Group also has the highest quality commitment in the industry. If you find a gray product produced by Jianzhi Group on the market, you will receive a reward of 1,618 RMB from Jianzhi Group. Therefore, there is absolutely no need to worry about quality problems when choosing the malleable pipe fittings of Jianzhi Group.

Each malleable pipe fitting is subjected to a pressure test

Strong supply ability

After 40 years of development, Jianzhi Group has become the largest manufacturer of malleable pipe fittings in China. We have two super-large malleable pipe fittings manufacturing plants in Tangshan City, Hebei Province, China and Chifeng City, Inner Mongolia, which can meet the annual production capacity of 40,000 tons. 

Coating Type

At present, Jianzhi Group's malleable pipe fittings are divided into three series according to their product design standards: heavy banded, medium beaded, and beaded. It can also be divided into three different types of pipe fittings based on the galvanizing method: hot-dip galvanizing, electro-galvanizing, and black products. Therefore, we can provide customers with 9 different choices for the same type of product.


l Heavy banded products: products that fully comply with the China national standard GB/T 3287-2011. The working temperature of the product is 200 degrees Celsius, and the working pressure is 1.6Mpa. Tensile strength>330Mpa, elongation>8%, hardness <150HB.

l Medium beaded products: products that meet the standards of construction and support enterprises. Its working strength standard fully meets the national standard, but in order to save costs, it is made smaller in size and thinner in wall thickness. During the production process of malleable, it is difficult to make the product thinner while maintaining the use standard. It is prone to through-hole phenomenon, and its strength and plasticity are also difficult to guarantee. Under the premise of ensuring the quality of products, medium beaded products have successfully reduced product costs and provided customers with more competitive price options.

l Beaded products: In order to meet the price demand of lower-end customers, Jianzhi Group has developed a series of beaded products. Heavy banded products can fully meet the strength requirements of the national standard, as can beaded products. Furthermore, mold release is easy due to the minimal changes in the design and filling capacity of the beaded products, resulting in even lower manufacturing costs.

l Hot-dip galvanizing: After the zinc ingot is dissolved by heating, a layer of zinc film is attached to the surface of the product through the hot-dip process. Through the isolation of the zinc layer, the product is protected from oxidation and rust is prevented. The advantage is that the coating is thick, the thickness of the inner and outer walls is uniform.

l Cold galvanizing: The product is passed through the electrolytic zinc solution, and the zinc ions are attached to the surface of the product under the action of the electrode to form a coating. The advantages are that the coating is uniform, the surface is smooth and beautiful, and the cost is low. The disadvantage is that the thickness of the coating is thin, and the coating on the inner surface is thin due to the magnetic effect of the electrodes. The product can be used in oil systems with low requirements for anti-oxidative corrosion.

l Non-galvanized black pipe fittings. This type of pipe fitting is malleable and does not require galvanizing, and the other steps are the same as the two above.

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Who is JIANZHI-malleable iron pipe fittings suppliers?

Founded in 1982, Jianzhi is a leading manufacturer and supplier of cast iron pipe fittings. Till now, Jianzhi has about 4,500 employees and more than 350 technical engineers with distributors covering over 100 countries around the world.

Jianzhi is committed to building a safer world by bringing premium cast iron pipe fittings to every household and building.


Cooperating with distributors all over the world and working to make the list grow is the business model of Jianzhi. Helping all partners to unleash their untapped potential and make profits is the service philosophy of Jianzhi.

On the manufacturing side, Jianzhi strictly controls the cost to ensure a stable supply of high-quality products and fast delivery.

On the marketing side, Jianzhi helps customers to formulate their marketing strategies. The over 90% reorder rate shows the recognition from every customer.

The production process of Jianzhi Malleable products

The production process of Jianzhi Malleable products is divided into modeling—melting—casting—annealing—polishing—correction—grinding—scraping—galvanizing— 10 major processes of threading.

1. modeling

Casting is a method of smelting metal, making a mold, pouring molten metal into the mold, and cooling and solidifying to obtain a casting with a certain shape and performance. There are many casting methods, which are often divided into sand casting and special casting. Jianzhi's malleable pipe fittings are produced by sand casting.

Sand casting refers to designing and making molds and core boxes according to the shape and size of the product, preparing molding sand and core sand, modeling with mold and molding sand, making cores with core boxes and core sand, and closing the box to obtain a mold. The metal is poured into the mold, and the casting is obtained after cooling and solidification.

Molding refers to the process of making molds in a casting program.

In order to ensure the dimensional accuracy of the mold, Jianzhi has built a mold production workshop and a mold repair workshop. All molds and core boxes are independently designed and produced.

At the same time, Jianzhi's mold production is all processed by high-precision CNC machine tools and automated machining centers, and its technical strength and equipment investment are second to none in the domestic industry.

In the use of molding sand, all Jianzhi products use first-grade water-washed sand with the highest specification to avoid mixing mud and stone, so as to ensure the smooth surface of the mold and the stability of the mold.

In the new factory area of Ning he in Jianzhi, Jianzhi has introduced the internationally advanced Faddier variable frequency rotor sand mixer to automatically process the molding sand to ensure the humidity and viscosity of the molding sand to improve the stability of the casting mold.

In terms of production technology, the old factory in Jianzhi Yutan still uses manual modeling technology, which is operated by old workers with many years of experience. In the new factory area of Shining, the international advanced automatic molding line was introduced, which improved the production efficiency and ensured the stability of the casting mold.

2. melting

Smelting refers to the process of heating raw metal materials to a molten state during the casting process in preparation for pouring.

Jianzhi's smelting process all uses electric furnaces for smelting. First, it avoids high air pollution caused by traditional cupola fuel combustion, which meets national environmental protection requirements. Casting defects caused by undercooling or overheating of the melt.

At the same time, Jianzhi has introduced an advanced on-line molten iron carbon and silicon analyzer to analyze the carbon content of iron-carbon alloys during the smelting process, decompose cementite, and ensure the metal composition and performance of castings.

3. Pouring: 

Pouring refers to the process of pouring the molten metal material into the mold and cooling and solidifying to obtain the casting.

4. Annealing

Annealing is a metal heat treatment process, which refers to slowly heating the metal to a certain temperature, holding it for a sufficient time, and then cooling it at a suitable rate. The purpose is to reduce hardness, improve machinability; eliminate residual stress, stabilize size, reduce deformation and crack tendency; refine grains, adjust organization, and eliminate organizational defects. To be precise, annealing is a heat treatment process for materials, including metallic materials and non-metallic materials. Moreover, the purpose of annealing of new materials is similar to that of traditional metal annealing.

Graphitization annealing refers to the decomposition of cementite Fe3C and the elimination of the existence of flake graphite structure (gray iron) during the annealing process. Forms a matrix of ferrite + flocculent graphite. If the annealing process is immature, there will be residual gray iron (flake graphite structure) in the core, and the section will be gray, which is what we call gray parts.

At the same time, due to the existence of supercooling during the casting and solidification process, there will be differences in the size of grain growth. Annealing can refine grains and improve the mechanical properties of castings.

Due to the volume change caused by the allotropy phenomenon during the solidification of the molten metal, internal stress will be generated. The annealing process can eliminate the residual internal stress, stabilize the size, and reduce the tendency of deformation and cracking.

The annealing process of malleable pipe fittings is carried out to achieve the above purpose.


Jianzhi Group has 35 years of casting experience and technical reserves, and has the strongest technical ability in the annealing process. At the same time, we use the international advanced tunnel annealing furnace, which effectively guarantees the product performance of the castings.

We often find the phenomenon of internal thread chipping on the products of other domestic manufacturers. In fact, this is a manifestation of unqualified annealing process technology, resulting in uneven casting material, high brittleness, and poor processing performance. Crash occurred.


5. Polishing

The castings obtained after the falling sand treatment must first undergo surface polishing treatment to obtain semi-finished products with smooth surfaces. The construction uses a centrifugal polishing machine, and balls are used as polishing materials. The steel balls and the castings are repeatedly ground in the centrifugal polishing machine to smooth the appearance.

6. correction

After polishing, if the roundness does not meet the requirements, or the surface shape does not meet the requirements of castings, the calibration process should be carried out to make the shape meet the requirements.

7. Grinding

For the corrected castings, the larger slag remaining on the surface after polishing should be removed by the grinding process, so as to have a beautiful appearance.

8. scraping 

Since the casting mold is usually designed with a large number of molds, the casting usually has the sprue designed for the casting mold and the flash generated by the pouring of the connecting channel. In the edging stage, these burrs are removed from the inner and outer surfaces of the casting by machining cuts.

9. Galvanizing

The galvanizing of Jianzhi is divided into two processes: hot-dip galvanizing and electro-galvanizing. In the previous section, we have described the two processes respectively.

The branch pipe fittings adopt the process of galvanizing first and then threading. In order to avoid the thread size deviation caused by the galvanized layer, ensure the smooth installation. At the same time, it also avoids the problem of thread knocking caused by product collision in the galvanizing process. This further ensures the smooth installation of the product during use.

10. Threading

The castings before the threading process are called blanks. Some customers, due to the requirements of the country or region, also directly purchase the blanks from our company, and perform threading processing in the country according to the requirements, so as to meet some special use requirements of the country or meet the requirements of the country of origin, so as to reasonably avoid some taxes.

Threading refers to machining the blanks according to the customer's requirements and machining threads of different national standards on the castings according to the customer's requirements.

Common pipe threads mainly include the following: NPT, PT, G, etc.

1) NPT is the abbreviation of National (American) Pipe Thread, which belongs to the American standard 60-degree tapered pipe thread, which is used in North America. For the national standard, please refer to GB/T12716-1991.

2) PT (BSPT) is the abbreviation of Pipe Thread. It is a 55-degree sealed conical pipe thread. It belongs to the Wyeth thread family. It is mostly used in Europe and the Commonwealth of Nations. T7306-2000. The domestic name is ZG.

3) G is a 55-degree unsealed pipe thread, which belongs to the Whitworth thread family. Marked as G stands for cylindrical thread. Refer to GB/T7307-2001 for the national standard.


Metric threads are represented by pitch, and American and British threads are represented by the number of threads per inch;

Metric threads are 60-degree equilateral threads, inch threads are isosceles 55-degree threads, and American threads are isosceles 60-degree threads;

Use metric units (such as mm) for metric threads, and imperial units (such as inches) for American and British threads;

"Insiders" usually use "cents" to refer to thread size, one-inch equals 8 points, 1/4 inch is 2 points, and so on.

In addition, there are: ISO - metric thread standard 60 degrees; UN - unified thread standard 60 degrees; API - American oil pipe thread standard 60 degrees; W - British Whitworth thread standard 55 degrees.


In my country, the metric thread standard was used in the earliest days of malleable pipe fittings, and the inch thread standard was gradually adopted in the later development. Therefore, the national standard thread of Jianzhi can be used in common with the British standard thread.


The thread standards used on malleable pipe fittings are all sealing thread standards to ensure that no leakage occurs.

In order to ensure the actual use effect of the pipe fittings and the smooth fit of the pipe threads, the branch pipe fittings should be designed to ensure the use space of the inner cavity as much as possible.

The national standard clearly stipulates the length of the pipe thread and the position of the base surface. The minimum length of the 1-inch tapered pipe internal thread using the retraction structure shall not be less than 11.6mm (about 5 pipe threads); the minimum length of the external thread shall not be less than 14.5mm (about 6.3 threads). In order to ensure the accurate position of the base surface, we always control the base surface of the tapered pipe thread in the best position during processing. The size of the base surface of the branch pipe fittings, that is, the thread accuracy is higher than the national standard. The national standard stipulates that it is ±1 1/4 buckle, and the branch pipe fittings stipulate and can be guaranteed to be within ±1 buckle.

There are two inspection methods for detecting the included angle of the pipe thread axis. One is to measure with a test rod, and the other is to detect with a goniometer. The principle of the two methods is the same, but the detection equipment and methods are different. The national standard stipulates that the angle deviation of the pipe thread should not exceed ±0.5°, and the branch pipe fittings should be controlled within ±0.3°, which is 40% stricter than the national standard.

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Contact Us

E-mail: sales1@jianzhi-fitting.com

Tel: +86 022 8848 8866

Office In Tianjin:

Heping District, Tianjin, China.

Production Base 1:

Chifeng, Inner Mongolia, China.

Production Base 2:

Tangshan City, Hebei Province, China.

Production Base 3:

Schelei Street,Baicoi City,Prahova County,Romania

Service email: info.ro@jianzhi-fitting.com

Sales email: market.ro@jianzhi-fitting.com

Tel: +40(755)011 849