Suzhou Xinsen Precision Casting Co.,Ltd

    Add: No.238, Qiushe Road, Qiushe Industrial Park, Tongli Town, Wujiang District, Suzhou City, Jiangsu, 215200, P.R.China

    Tel: 86-512-63375886-608


    Fax: 86-512-63370558

    QQ: 502082393


Home > News > Content

Valve Pipe Casting To Prevent Long-term Impact Of Molten Iron

1, structural analysis

(1) The disc is a garden-shaped structure, the internal cavity is supported by eight ribs, the top Φ620 hole and the cavity connected, the rest are closed shape, sand core is difficult to fixed, and easy to deformation, while the sand Core exhaust and cavity cleaning have brought great difficulties,

(2) Valve Pipe Casting wall thickness difference is great, the maximum wall thickness of 380mm, the minimum wall thickness of only 36mm. Valve Pipe Casting solidification when the temperature difference is large, uneven shrinkage easily produce shrinkage, shrinkage defects caused by water pressure test seepage.

2, the process design:

1. Part of the surface shown in Figure 1, will be one end of the hole on the box, the middle cavity to do a whole sand core, the core of the appropriate lengthened to facilitate the tightening of the sand core and box when the sand core stability , The two sides of the blind hole cantilever core length is greater than the length of the hole, so that the entire center of gravity sand core side of the core to ensure that the sand core fixed smooth.

2, the use of semi-enclosed gating system, ΣF: ΣF horizontal: ΣF straight = 1: 1.5: 1.3, with diameter diameters of Φ120 ceramic tube, the bottom placed two 200 × 100 × 40mm refractory bricks to prevent Hot water directly impact sand mold, the bottom of the runner 150 × 150 × 40 foam ceramic filter, the inner runner with 12 diameter Φ30 ceramic tube through the bottom of the filter tank connected to the bottom of the Valve Pipe Casting to form the bottom of the pouring pouring program,

(3) on the mold placed 14 ∮ 20 cavity cavity, the middle of the core placed a Φ200 sand core exhaust hole, placed in the thick part of the cold iron chill, to ensure that the Valve Pipe Casting to achieve a balanced solidification, the use of graphitization expansion principle canceled Fill the riser to improve the production rate, sand box size 3600 × 3600 × 1000 / 600mm, with 25mm thick steel plate welding to ensure adequate strength and rigidity,

3, process control

(1) shape: before modeling with Φ50 × 50mm standard sample testing resin sand compressive strength ≥ 3.5MPa ,, cold iron and sprue parts focus tightly to ensure that the sand mold has enough strength to offset the molten iron solidification generated when the graphite The expansion and prevent the molten iron for a long time impact on the parts of the runner caused by sand.

(2) core: the sand core by the eight ribs will be divided into 8 points of the entire sand core, through the middle cavity connected, in addition to the middle of the core outside the other support and exhaust parts, such as can not handle the sand Core fixed and exhaust, pouring will appear after the sand core displacement and stomata, due to the overall size of the sand core, and was divided into eight parts, must have sufficient strength and rigidity in order to ensure that the sand core from the mold after the damage, Pouring does not occur after the deformation phenomenon, so as to ensure the uniformity of the Valve Pipe Casting wall thickness, for which we have made a special core, and with the ventilation rope on the core above the core from the exhaust, the core to ensure that the sand mold tight Reality,

(2) box: consider the disc valve cavity sand for the difficult, the entire sand core brushing two layers of paint, the first layer of brush alcohol base zirconium coating (Pomeranian 45-55), until the first layer of coating After drying and then the second layer of Alcohol-based coating (Bobby 35-45) to prevent the sticking sand and sintering, can not be cleaned. Core parts with three M25 screw hanging in the core of the main structure Φ200 steel pipe with the upper mold sand with a screw to take a fixed lock and check the wall thickness is uniform.

4, melting pouring process

(1) with Benxi low P, S, Ti quality Q14 / 16 # pig iron, according to the proportion of 40% to 60%; scrap strictly control P, S, Ti, Cr, Pb and other trace elements, , Adding the proportion of 25% to 40%; back to the charge before use to be shot clean clean, to ensure that the charge clean.

(2) Furnace main component control: C: 3.5-3.65%, Si: 2.2% ~ 2.45%, Mn: 0.25% ~ 0.35%, P≤0.05%, S: ≤ 0.01%, Mg (residual): 0.035% ~ 0.05%, in the premise of ensuring the ball, Mg (residual) as much as possible to take the lower limit.

(3) spheroidization treatment: the use of low magnesium low rare earth spherulite, adding the ratio of 1.0% to 1.2%, conventional into the ball spheroidization treatment, a 0.15% coverage in the package at the end of the ball agent, Slag and then subcontracted for the second birth of 0.35%, pouring with the flow of pregnant 0.15%

(4) the use of low-temperature fast Valve Pipe Casting process, pouring temperature 1320 ℃ ~ 1340 ℃, pouring time 70 ~ 80s, pouring molten iron can not be cut, the gate cup is always full of state, to prevent gas and inclusions through the ladle Cavity.

5, Valve Pipe Casting test results

1. Test the tensile strength of the test piece: 485MPa, elongation: 15%, Brinell hardness HB187.

2. Spheroidization rate of 95%, graphite size 6, pearlite 35%, microstructure shown in Figure 5.

3. Important parts UT, MT secondary detection found no record defects.

4. Appearance smooth and smooth, no sand, slag, cold and other Valve Pipe Casting defects, uniform wall thickness, size to meet the requirements of the drawings.

5. After processing 20kg / cm2 water pressure test did not appear leakage phenomenon.

Contact Us
Address: No.238, Qiushe Road, Qiushe Industrial Park, Tongli Town, Wujiang District, Suzhou City, Jiangsu, 215200, P.R.China
Tel: +86-512-633758+86-608