Rare earth magnesium silicon iron alloy

Rare earth magnesium silicon iron alloy

Description

Rare earth magnesium ferrosilicon alloy is widely used as a spheroidizing agent in various grades of ductile iron. It can replace some tasks that cannot be accomplished by steel castings or steel castings. It is used in various fields such as military industry, space navigation, high-speed railway, automobile agricultural machinery and civil machinery. It is China's main strategic material. ......

  • product description

Spheroidizing agent and ductile iron

Rare earth magnesium ferrosilicon alloy (spheroidizing agent)

Rare earth magnesium ferrosilicon alloy is widely used as a spheroidizing agent in various grades of ductile iron. It can replace some tasks that cannot be accomplished by steel castings or steel castings. It is used in various fields such as military industry, space navigation, high-speed railway, automobile agricultural machinery and civil machinery. It is China's main strategic material.

Because the graphite in the production is in the form of flakes and layered crystals, because the bonding strength between the graphite layers is weak and easy to slide, the strength is low and the toughness is small, and the mechanical and physical properties of the engineering materials are often not met, in order to solve this problem, The molten iron is spheroidized so that all or most of the graphite in the molten iron is converted into a spherical shape. The alloy for treating molten iron is a spheroidizing agent, and the treated cast iron is ductile iron.

In the ductile iron, the graphite is spherical, which makes the basic change of the matrix, the strength of the casting is greatly improved, the toughness is increased, the mechanical and physical properties of the casting are greatly improved, and the ductile iron castings are widely applied to all aspects of construction machinery.

From the mechanical properties of the ductile iron grade and the GB/T1348-2009 national standard of the matrix structure , the tensile strength σb is from 350-900 MPa and the elongation is up to δ22%, which is completely different from the gray cast iron and the mechanical properties of the vermicular graphite cast iron. . The production of ductile iron is also an indispensable process. The method of using the spheroidizing agent is simple, and the current spheroidal graphite cast iron production adopts the rushing method, and this method is introduced in various literature works.

The grade selection of the spheroidizing agent is determined based on the sulfur content and carbon equivalent in the original molten iron. According to the spheroidizing agent GB/T28702-2012 standard.

The S content is <0.03%, the="" carbon="" equivalent="" is=""><4.26%, and="" the="" 4-1="" to="" 7-2="" grade="" spheroidizing="" agent="" is="">

The S content is 0.04-0.05%, the carbon equivalent is >4.26%, and the 8-3 to 8-5 grade spheroidizing agent is used.

The S content is more than 0.06%, the carbon equivalent is >4.6% or more, and the 8-7 grade is used. The GB/T4138-2004 standard can also be produced according to the user's requirements to produce a product containing a high amount of RE and Mg.

The manufacturer determines whether the amount of spheroidizing agent added is correct by the amount of Mg residual and the amount of RE remaining in the casting, and determines whether the casting is qualified.

The amount of Mg residue and RE residue in the casting are determined according to the thickness of the spheroidized casting:

Casting thickness

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30-70mm

70-130mm

130-250mm

Residual Mg%

0.03-0.04

0.03-0.045

0.035-0.05

0.03-0.08

Remnant RE%

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0.02-0.03

0.03-0.04

0.01-0.02

The content of Mg residual and RE residual in the casting is high, and the qualified rate of the casting is high. Otherwise, the residual Mg is out of the pore, and the residual height of RE produces cementite (ie, white mouth).

The amount of the spheroidizing agent can also be adjusted according to the size of the white mouth of the triangular test piece, and the normal addition amount is preferably controlled at 1.2-1.3%.

Our company's product supply granularity is 5-35mm, this particle size is applied to 500-1200kg ladle, and other granular users will agree on the contract when ordering.

Mechanical properties and matrix structure of nodular cast iron grades GB/T1348-2009

Material grade

tensile strength

Σb/MPa

Yield limit σ 0.2/MPa

Elongation%

δ

Brinell hardness

HBW

Matrix organization

QT350-22L

350

220

twenty two

≤160

Ferrite

QT350-22R

350

220

twenty two

≤160

Ferrite

QT350-22

350

220

twenty two

≤160

Ferrite

QT400-18L

400

240

18

120-175

Ferrite

QT400-18R

400

250

18

120-175

Ferrite

QT400-18

400

250

15

120*-175

Ferrite

QT400-15

400

250

15

120-180

Ferrite

QT450-10

450

310

10

160-210

Ferrite

QT500-7

500

320

7

170-230

Ferrite + pearlite

QT550-5

550

350

5

180-250

Ferrite + pearlite

QT600-3

600

370

3

190-270

Pearlite + ferrite

QT700-2

700

420

2

225-305

Pearlite

QT800-2

800

480

2

245-335

Bead + cable + tempering Markov or troostite

QT900-2

900

600

2

280-360

Qur's body + sorbite

Note: The letter “L” indicates that the grade has low impact performance (-20°C or -40°C).

The letter "R" indicates that the grade has an impact performance requirement at room temperature (23 ° C).

Rare earth magnesium ferrosilicon alloy (spheroidizing agent) grade and chemical composition GB/T28702-2012

Serial number

Brand

chemical composition%

Abbreviation

Brand

Mg

RE

Si

Ai

Ti

1

Mg4RE

3.5-4.5

>0-1.5

≤4.8

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4-1

2

Mg4RE2

3.5-4.5

>1.5-2.5

≤4.8

<>

<>

4-2

3

Mg5RE

>4.5-5.5

>0-1.5

≤4.8

<>

<>

5-1

4

Mg5RE2

>4.5-5.5

>1.5-2.5

≤4.8

<>

<>

5-2

5

Mg6RE

>5.5-6.5

>0-1.5

≤4.8

<>

<>

6-1

6

Mg6RE2

>5.5-6.5

>1.5-2.5

≤4.8

<>

<>

6-2

7

Mg6RE3

>5.5-6.5

>2.5-3.5

≤4.8

<>

<>

6-3

8

Mg7RE

>6.5-7.5

>0-1.5

≤4.8

<>

<>

7-1

9

Mg7RE2

>6.5-7.5

>1.5-2.5

≤4.8

<>

<>

7-2

10

Mg8RE3

>7.5-8.5

>2.5-3.5

≤4.8

<>

<>

8-3

11

Mg8RE5

>7.5-8.5

4.5-5.5

≤4.8

<>

<>

8-5

12

Mg8RE7

>7.5-8.5

6.5-7.5

≤4.8

<>

<>

8-7

  1. Density: 4.0-4.6g/cm3

  2. Appearance: Irregular block, bright silver gray, not powdered and contains inclusions.

  3. Supply size (mm): 5-35, other sizes are determined by the contract between the supplier and the buyer.

  4. Melting point: 1100-1180 °C

  5. It is packed in anti-moist plastic woven bag with a net weight of 25kg and is accompanied by a product certificate.


Our company produces related products of rare earth magnesium alloy series.

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