Spheroidal graphite cast pipe with anti-corrosion and anti-scaling inner wall for water supply pipe network

Abstract

An inner wall anti-corrosion and anti-scaling spheroidal graphite cast iron pipe for a water supply pipe network comprises a spheroidal graphite cast iron pipe base body layer, an alloy transition layer and an anti-scaling layer which are sequentially arranged from outside to inside, the inner wall of the anti-scaling layer is provided with a super-hydrophobic surface, the Vickers hardness is larger than or equal to HV1200, and the alloy transition layer is made of an anti-corrosion alloy material. The anti-scale layer comprises a base layer and meshing ribs spirally arranged on the inner surface of the base layer in the axis direction, the base layer is metallurgically bonded to the inner surface of the spheroidal graphite cast pipe base body layer through the centrifugal casting technology, the meshing ribs are distributed intermittently in the spiral extending direction, and the anti-scale layer is bonded with the alloy transition layer through the mechanical embedding effect of the meshing ribs. By adopting a composite structure combining mechanical embedding and metallurgy, the interface strength is remarkably improved, and the alloy transition layer and the anti-scaling layer can be effectively prevented from being stripped, so that the efficient corrosion resistance, scaling resistance and wear resistance of the inner wall of the spheroidal graphite cast iron pipe are greatly improved, and the spheroidal graphite cast iron pipe has remarkable technical advantages and economic values in areas with poor water quality and industrial scenes with high added values.

Description

TECHNICAL FIELD

[0001] The utility model relates to water supply pipe design technical field, specifically is a kind of inner wall corrosion and scale resistance nodular cast pipe for water supply pipe network. BACKGROUND

[0002] Nodular cast pipe is widely used in water supply pipe network due to high strength and good toughness, but its inner wall is easy to be corroded and scale deposition for long-term contact with water. The traditional corrosion and scale resistance measures are to use cement mortar or epoxy coating lining, but there is a problem that coating is easy to fall off, leading to corrosion and scale resistance failure, so regular maintenance is needed, but frequent maintenance also needs frequent excavation, which is troublesome, and in some poor water quality areas or high value-added industrial scenarios, the downtime cost of single maintenance is far more than the cost of nodular cast pipe maintenance. SUMMARY

[0003] To solve the technical problems in the above background art, the utility model provides a kind of inner wall corrosion and scale resistance nodular cast pipe for water supply pipe network.

[0004] The utility model technical scheme is as follows:

[0005] A kind of inner wall corrosion and scale resistance nodular cast pipe for water supply pipe network, including nodular cast pipe base layer, alloy transition layer and scale prevention layer sequentially arranged from outside to inside, wherein the inner wall of scale prevention layer is super-hydrophobic surface, and Vickers hardness is HV1200, alloy transition layer is made of corrosion-resistant alloy material, specifically, alloy transition layer includes base layer and the interlocking rib spirally arranged along the axis direction on the inner surface of base layer, base layer is metallurgically combined to the inner surface of nodular cast pipe base layer by centrifugal casting process, the interlocking rib is discontinuously distributed in the spiral extension direction, and scale prevention layer is combined with alloy transition layer by the mechanical embedding effect of interlocking rib.

[0006] The nodular cast pipe adopts three-layer composite structure to improve the corrosion and scale resistance performance of its inner wall, specifically, to ensure the overall strength and toughness of the nodular cast pipe, the outer layer is designed to retain the nodular cast pipe base, then based on the nodular cast pipe base, the base layer of corrosion-resistant alloy material is metallurgically combined on the inner wall by centrifugal casting process, so as to enhance the interfacial adhesion, avoid the peeling of corrosion-resistant layer, and the interlocking rib is designed on the inner wall of base layer, so that the attachment surface of scale prevention layer becomes rough, thereby increasing the bonding area of scale prevention layer and alloy transition layer, thereby greatly improving the bonding strength of scale prevention layer and alloy transition layer.

[0007] In addition, the design of discontinuous interlocking rib also facilitates rapid manufacturing, and the interlocking rib can be made by arc cladding or laser cladding process, and both of the two manufacturing methods can meet the bonding strength requirement in most cases, and laser cladding process can be preferred for higher bonding strength requirement.

[0008] Preferably, the interlocking ribs comprise a plurality of rib segments discontinuously distributed along the spiral extension direction, and the plurality of rib segments are arranged staggeredly along the axial direction, so as to form a concave-convex interlocking structure on the surface of the alloy transition layer, and the anti-fouling layer material can penetrate into the interlocking rib gaps during forming, so that the anti-fouling layer can still release stress through the rib gap during thermal expansion / contraction, while maintaining the interface bonding strength, and can form physical interlocking with the rib after the anti-fouling layer is solidified, thereby improving the ability to resist axial shear force and circumferential peeling force.

[0009] In terms of comprehensive cost and process stability, the axial spacing of adjacent rib segments is 15mm-30mm.

[0010] The interlocking ribs are made by arc cladding or laser cladding process, and for the case of high bonding strength, laser cladding process is preferred.

[0011] The cross-sectional shape of the interlocking rib is trapezoidal to enhance structural rigidity.

[0012] The top of the interlocking rib, the root of the interlocking rib and the base layer are circularly structured to reduce stress concentration.

[0013] The height size of the interlocking rib is 30%-45% of the thickness size of the alloy transition layer.

[0014] The bottom width of the interlocking rib is greater than the top width.

[0015] The alloy transition layer is a nickel-based alloy transition layer.

[0016] The contact angle of the super-hydrophobic surface of the anti-fouling layer is greater than 150°, and the anti-fouling layer is an organic fluorine coating or an inorganic fluorine coating.

[0017] The thickness ratio of the ductile cast pipe base layer, the alloy transition layer and the anti-fouling layer is: (6.0-8.0):(1.0-1.5):(0.2-0.5), and as preferably, the thickness ratio of the ductile cast pipe base layer, the alloy transition layer and the anti-fouling layer can be specifically 7:1.5:0.3, which can be applied to DN100-DN1200 caliber ductile cast pipes after testing.

[0018] The utility model relates to a kind of inner wall corrosion-resistant anti-fouling ductile cast pipes for water supply pipe network, which combines the three-layer composite structure of mechanical fitting and metallurgical combination, significantly improves interface strength, can effectively prevent alloy transition layer and anti-fouling layer peeling, thereby greatly improves the efficient corrosion-resistant, anti-fouling and wear resistance of the ductile cast pipe inner wall, although initial investment is higher than traditional process, but no frequent excavation maintenance is needed, in water quality poor area and high value-added industrial scene, it has significant technical advantage and economic value. BRIEF DESCRIPTION OF DRAWINGS

[0019] In the drawings:

[0020] Figure 1 Fig. 1 is a schematic view of the cross-sectional structure of the inner wall of the ductile cast pipe for water supply network (partly shown) according to the present embodiment;

[0021] Figure 2 Fig. 2 is a schematic view of the discontinuous distribution path of the ribbing of the occlusion rib according to the present embodiment;

[0022] Figure 3 Fig. 3 is an enlarged schematic view of A in Fig. 1; Figure 1 Fig. 4 is an enlarged schematic view of B in Fig. 1;

[0023] The components represented by the reference numerals in the drawings are as follows:

[0024] 1, ductile cast pipe base layer; 2, alloy transition layer; 21, base layer; 22, occlusion rib; 221, ribbing; 3, anti-fouling layer. DETAILED DESCRIPTION

[0025] In combination with the prior art, Figure 1 and Figure 2 The present embodiment provides a ductile cast pipe for water supply network with anticorrosion and anti-fouling inner wall, which comprises, from outside to inside, a ductile cast pipe base layer 1, an alloy transition layer 2 and an anti-fouling layer 3.

[0026] The alloy transition layer 2 comprises a base layer 21 and an occlusion rib 22 spirally arranged on the inner surface of the base layer 21 along the axial direction, the base layer 21 is metallurgically combined to the inner surface of the ductile cast pipe base layer 1 by centrifugal casting process, the occlusion rib 22 is discontinuously distributed in the spiral extension direction, and the anti-fouling layer 3 is combined with the alloy transition layer 2 by the mechanical embedding effect of the occlusion rib 22.

[0027] Specifically, the alloy transition layer 2 is made of a corrosion-resistant alloy material, and the alloy transition layer 2 is a nickel-based alloy transition layer, for example, a commonly used Ni-Cr-Mo alloy. In addition to corrosion resistance, the thermal expansion coefficient is also matched with the ductile cast pipe.

[0028] The anti-fouling layer 3 can be selected from commonly used fluoride coatings, including organic fluoride coatings or inorganic fluoride coatings. In the present utility model, a chromium carbide-fluorinated polymer composite coating or a fluorinated diamond-like carbon coating is preferred. Such coatings can construct the inner wall into a super-hydrophobic surface (contact angle > 150°), thereby reducing water contact, inhibiting mineral deposition, breaking the continuity of the electrolyte, reducing electrochemical corrosion, and the inner wall of the anti-fouling layer 3 can have a Vickers hardness ≥ HV1200. For cases with higher life requirements, the anti-fouling layer 3 preferably uses a fluorinated diamond-like carbon coating.

[0029] The nodular cast pipe adopts a three-layer composite structure to improve the anticorrosion and anti-fouling performance of the inner wall, specifically, for the outermost layer of the nodular cast pipe base layer 1, the nodular cast iron base is retained to ensure the overall strength and toughness of the pipe, then based on the nodular cast pipe base, a metallurgical bond with a high corrosion resistance base layer 21 is realized on the inner wall through the centrifugal casting process, thereby enhancing the interfacial adhesion and avoiding the peeling of the corrosion-resistant layer, and at the same time, the base layer 21 is designed with interlocking ribs 22 on the inner wall, which makes the adhesion surface of the anti-fouling layer 3 rough, thereby increasing the bonding area of the anti-fouling layer 3 and the alloy transition layer 2, and greatly improving the bonding strength of the anti-fouling layer 3 and the alloy transition layer 2.

[0030] Among them, the design of the interlocking rib 22 discontinuous rib 221 is also convenient for rapid manufacturing, and the interlocking rib 22 can be made by electric arc cladding or laser cladding process, both of which can meet the bonding strength requirements in most cases, and for some higher bonding strength requirements, laser cladding process can be preferred.

[0031] In combination Figure 2 The interlocking rib 22 includes a plurality of rib segments 221 discontinuously distributed along the spiral extension direction, and the plurality of rib segments 221 are staggered along the axial direction, thereby forming a concave-convex interlocking structure on the surface of the alloy transition layer 2, so that the anti-fouling layer 3 material can penetrate into the gap between the interlocking ribs 22 when forming, so that the anti-fouling layer 3 can still release stress through the gap between the rib segments 221 when thermal expansion / contraction, while maintaining the interfacial bonding strength, and can form physical interlocking with the rib segments 221 after the anti-fouling layer 3 solidifies, improving the ability to resist axial shear force and circumferential peeling force.

[0032] In terms of overall cost and process stability, the axial spacing between adjacent rib segments 221 of the interlocking rib 22 is 15-30 mm.

[0033] The interlocking rib 22 is made by electric arc cladding or laser cladding process in the existing process, and for high bonding strength, laser cladding process is preferred

[0034] It should be noted that since the interlocking rib 22 is formed by subsequent processing, its material can be the same as the base layer 21, which is a nickel-based alloy, or it can choose another material, which is not listed here.

[0035] In combination Figure 3 The cross-sectional shape of the interlocking rib 22 is trapezoidal to enhance the structural rigidity, and the top of the interlocking rib 22 and the root of the interlocking rib 22 are circularly structured to reduce stress concentration.

[0036] The height of the interlocking rib 22 is 30-45% of the thickness of the alloy transition layer 2, and the bottom width of the interlocking rib 22 is greater than the top width.

[0037] The thickness ratio of the ductile cast pipe base layer 1, the alloy transition layer 2 and the anti-fouling layer 3 is (6.0-8.0):(1.0-1.5):(0.2-0.5), preferably, the thickness ratio of the ductile cast pipe base layer 1, the alloy transition layer 2 and the anti-fouling layer 3 can be 7:1.5:0.3, which can be applied to DN100-DN1200 caliber ductile cast pipes through experiments.

[0038] (1.0-1.5):(0.2-0.5), preferably, the thickness ratio of the ductile cast pipe base layer 1, the alloy transition layer 2 and the anti-fouling layer 3 can be 7:1.5:0.3, which can be applied to DN100-DN1200 caliber ductile cast pipes through experiments.

[0039] The utility model discloses a kind of inner wall corrosion-resistant anti-fouling ductile cast pipes for water supply pipe network, which combines the three-layer composite structure of mechanical fitting and metallurgy, significantly improves interface strength, can effectively prevent alloy transition layer 2 and anti-fouling layer 3 peeling, thereby greatly improve the high-efficiency corrosion-resistant, anti-fouling and wear resistance of the ductile cast pipe inner wall, although initial investment is higher than traditional process, without frequent excavation maintenance, in water quality bad area and high value-added industrial scene, with significant technical advantage and economic value.

Claims

1. A nodular cast pipe for water supply network with inner wall corrosion and scale resistance, characterized in that, The anti-fouling layer (3) is an inner wall of a super-hydrophobic surface, and the Vickers hardness is greater than or equal to HV1200. The alloy transition layer (2) is made of corrosion-resistant alloy material, and includes a base layer (21) and an engagement rib (22) spirally arranged along the axial direction on the inner surface of the base layer (21); The base layer (21) is metallurgically combined with the inner surface of the ductile cast iron pipe base layer (1) through a centrifugal casting process, the engagement rib (22) is discontinuously distributed in the spiral extension direction, and the anti-fouling layer (3) is combined with the alloy transition layer (2) through the mechanical embedding effect of the engagement rib (22). The engagement rib (22) includes a plurality of rib segments (221) discontinuously distributed along the spiral extension direction, and the plurality of rib segments (221) are staggered along the axial direction.

2. A nodular cast pipe for water supply network with inner wall corrosion and scale resistance according to claim 1, characterized in that, The axial spacing between adjacent rib segments (221) is 15mm-30mm.

3. A nodular cast pipe for water supply network with inner wall corrosion and scale resistance according to claim 2, characterized in that, The cross-sectional shape of the engagement rib (22) is trapezoidal, and the top is a rounded structure.

4. A nodular cast pipe for water supply network with inner wall corrosion and scale resistance according to claim 1, characterized in that, The height dimension of the engagement rib (22) is 30%-45% of the thickness dimension of the alloy transition layer (2).

5. A nodular cast pipe for use in water supply networks with internal anticorrosive and anti-fouling coating according to claim 4, characterized in that, The bottom width of the engagement rib (22) is greater than the top width.

6. A nodular cast pipe for use in water supply networks with internal anticorrosive and anti-fouling coating, according to claim 5, characterized in that, The alloy transition layer (2) is a nickel-based alloy transition layer.

7. A nodular cast pipe for use in water supply networks with internal anticorrosive and anti-fouling coating according to claim 1, characterized in that, The anti-fouling layer (3) is an organic fluorine compound coating or an inorganic fluorine compound coating.

8. A nodular cast pipe for water supply network with inner wall corrosion and scale resistance as claimed in claim 1 wherein, The thickness ratio of the ductile cast iron pipe base layer (1), the alloy transition layer (2) and the anti-fouling layer (3) is (6.0-8.0):(1.0-1.5):(0.2-0.5).

9. A nodular cast pipe for water supply network inner wall corrosion and scale resistance according to any one of claims 1 to 8, characterized in that, The engagement rib (22) is made of electric arc cladding or laser cladding process.

10. A nodular cast pipe for use in water distribution networks having an internal anticorrosive and anti-fouling coating, according to claim 9, characterized in that, ​

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