CN100387744C - Boron phosphor alloy continuous casting section bar for iron casting and its production method - Google Patents

Abstract

The present invention relates to a boron-phosphorus alloy cast iron continuous-cast profile and a preparation method thereof. The continuous-cast profile of the present invention is prepared from C, Si, Mn, Cr, Mo, Cu, B, P, S, Sb, Ti and Fe. The present invention has the advantages that the Cr, the Mo, and the Cu are used for strengthening the solid solution so as to enhance the collective electric potential effect, and the C is diffused in Fe3(C1B) and Fe23(C1B)6 (carbon borides) so as to change the hardness mass point (Hx is equal to 1150); the P has the outstanding functions of refining the phosphorus eutectic crystal network, refining the graphite eutectic crystals and stabilizing the perlite; the Sb increases and stabilizes the amount of the perlite; the comprehensive effect of the boron-phosphorus alloy cast iron continuous-cast profile is obvious under the lubricated condition, the lubricating properties of oil bearing and oil storage of graphite sheets cooperate with the hard point borides and phosphorus eutectic crystals on the first grinding surface, and the oil storage property of the matrix on the second grinding surface so as to keep the continuity of the lubricating oil film and give prominence to the wear-resistant function of the hardening and the network; the characteristics of corrosion resistance and wear resistance existing in the solid-solution strengthened and hardened phase is manifested by the quench tempering treatment.

Description

Boron phosphor alloy continuous casting section bar for iron casting and manufacture method thereof

Technical field

The present invention relates to a kind of cast alloy iron continuous casting section bar, relate in particular to a kind of high abrasion, against corrosion, fatigue proof boron phosphor alloy continuous casting section bar for iron casting and manufacture method thereof under temperature burn into pressure working condition condition.

Background technology

On the basis of cast alloy iron, the multi-element alloyed effect that re-adds boron, phosphorus, antimony, titanium, be used widely in fields such as current cam at internal combustion engine cylinder jacket, piston, weaving loom, rotor, shuttle nose, environment-friendly air conditioner compressor piston.

With the household electrical appliances air-conditioning is example, prevent the destruction of atmospheric ozone layer, environment-friendly air conditioner is the current important topic that faces, its cardiac part piston, when it is long in cold and hot conversion temp field, working under the pressure-changed condition of the corrosive nature of New Refrigerating medium, gasification compression, so take all factors into consideration the heatproof of material, withstand voltage, anti-corrosion, fatigue performance, is to improve complete machine work-ing life and energy-efficient gordian technique.

How to produce this cast alloy iron continuous casting section bar and be pendulum and in face of the science and technology personnel, need the problem that solves.

Summary of the invention

The technical issues that need to address of the present invention have provided a kind of boron phosphor alloy continuous casting section bar for iron casting, are intended to solve the above problems.

The present invention also provides a kind of method of making this boron phosphor alloy continuous casting section bar for iron casting.

In order to solve the problems of the technologies described above, the present invention is achieved by the following technical solutions:

Boron phosphor alloy continuous casting section bar for iron casting of the present invention is made up of C, Si, Mn, Cr, Mo, Cu, B, P, S, Sb, Ti, Fe; Its weight (%) is than being C:3.00-3.6, Si:1.80-2.90, Mn:0.40-0.80, Cr :≤0.20, Mo:0.10-0.50, Cu:0.40-1.00, B:0.02-0.15, P:0.30-0.80, S :≤0.06, Sb:0.02-0.15, Ti:0.08-0.15, Fe: surplus.

Manufacture method of the present invention realizes by following steps:

Melting: adopt induction furnace or cupola furnace---the melting mode of induction furnace; Melting technology comprises:

Base iron, stokehold Rapid Thermal analyser controlled contents: carbon 3.20-3.60% and silicon 2.20-2.90%;

The alloy hot metal smelting temperature is 1460～1500 ° Celsius;

The method that pours in the hot metal ladle breeds, and 1400～1420 ° Celsius of pregnant preceding molten iron temperature breeds 7～9 minutes time length, breeds dosage 0.4～0.8%, nucleating agent granularity＜12mm.

Section bar spectroscopic analysis: determine Cr, Mo, Cu, Ti, Mn, S, P, Sb content;

The continuous casting drawing;

Mold structure;

The adjustment of temperature of cooling water, flow, pressure;

The adjustment of crystallizer outlet section bar surface temperature;

The adjustment of section bar pulling speed;

Compared with prior art, the invention has the beneficial effects as follows: strengthen solid solution at CrMoCu and improve outside collective's current potential effect, B is with disperse Fe ₃(C ₁B) and Fe ₂₃(C ₁B) ₆Carbon boride hardening degree particle (Hx=1150); And P is with the refinement iron phosphide eutectic network, the refinement graphite eutectic that protrude with stablize pearlitic effect, and Sb impels either pearlite occurred to increase and be stable; Comprehensive action highlights to be had under the lubricating condition, with the lubricated characteristic of the oil-containing oil storage of graphite flake, cooperate hard point boride, the iron phosphide eutectic of first flour milling, the matrix self-enrichment of second flour milling, not only keep the continuity of oil-bound film but also highlighted the wear-resisting effect of sclerosis and network, handle by Q-tempering and just more to manifest solution strengthening and mutually against corrosion of hardening, antiwear characteristic.

Embodiment

Following embodiment describes in further detail the present invention:

Boron phosphor alloy cast iron continuous casting rod section bar chemical ingredients scope is divided into high and low intensity two-stage by intensity rank.

With air-conditioning 410A piston is example: σ b 〉=200N/mm ²The level bar.

High strength LZBPHT300 (σ b ≈ 300N/mm ², HB ≈ 200～240) the bar chemical constitution:

Low strength LZBPHT200 (σ b ≈ 200N/mm ², HB ≈ 160～200) the bar chemical constitution:

The chemical composition design principle of BP cast alloy iron continuous casting material of the present invention:

Control carbon equivalent (CE) and greying coefficient (K) in the chemical ingredients and adjust the tissue and the performance of cast iron;

Main silicon (Si) is referred and synthesized into suitable carbon amount with phosphorus (P) in the cast iron, and it and actual carbon amount sum become carbon equivalent ce:

CE＝C+(Si+P)/3

C, Si, P respectively are the content (%) of carbon, silicon, phosphorus in the cast iron

The CE scope of BP cast alloy iron LZBPHT200～300 controls is 4.10～4.30 at present).

The influence of cast iron degree of graphitization mainly be the acting in conjunction of considering C and Si, and greying coefficient formula K=4/3Si (1-5/ (3C+Si)) is an effective tool of differentiating the CrMoCu structure of cast iron:

When K≤0.65, cast iron is complete white tissue

When 0.65＜K≤0.8, matrix is that perlite adds cementite fiber crops mouthful tissue

When 0.85＜K≤2.05, matrix is that perlite adds ferrite ash mouthful tissue

When K＞3.10, matrix is a ferritic structure

Under 0.85＜K≤2.05 situations, when the content of interpolation Cr, Mo, Cu, Sb is adjusted pearlitic quantity of matrix and the increase of thickness degree alloy content, either pearlite occurred increases and refinement, improves the homogeneity of structure of casting section simultaneously, and they are to adjust other responsive element of casting strength level.

The add-on of boron (B) is controlled at 0.03～0.08% scope, because of B to the greying effect of drawing up, Quench tendency is arranged in the process of setting, low B structure of cast iron changes hardly, but in the tissue graphite and carbide refinement, B with Fe ₃C-Fe ₂The compound cementite of B becomes disperse and distributes, and its hardness can reach HV1150 (HR in matrix _C＞70), its fusing point height, corrosion stability is good, is difficult for producing the corrosion phenomenon in the work.

Binary iron phosphide eutectic (Fe appears in phosphorus P with the iron phosphide eutectic form ₃P+ point-like austenite resolvent), ternary iron phosphide eutectic (Fe ₃P+Fe ₃C+ point-like austenite resolvent), iron phosphide eutectic is interrupted network and is distributed on the crystal boundary acting on simultaneously with Cu and Ti, can refining eutectic group, stablize perlite, and impel the increase of intensity and hardness.

The manufacture method of BP cast alloy iron continuous casting bar of the present invention realizes by following steps: the continuous casting process parameter

Melting:

According to the full and uniform requirement of alloy melting composition,, keep stable hot metal composition and molten iron temperature according to inherence tissue and different shapes size bar situation.Usually adopt electric furnace or cupola furnace---the melting mode of electric furnace.

A. base iron, stokehold Rapid Thermal analyser control carbon and silicone content %, CE are 3.9～4.2 scopes;

B. the alloy hot metal smelting temperature is 1460～1500 ° Celsius;

C. the method that pours in the hot metal ladle breeds, pregnant before 1400～1420 ° Celsius of temperature, breed 7～9 minutes time length, nucleating agent granularity＜12mm, pregnant amount 0.4～0.8%

D. section bar spectroscopic analysis: determine P, S, Cr, Mo, Cu, Sb, Ti equal size, and adjust according to the use properties of component of machine, intensity, hardness and the matrix situation of comprehensive section bar, the actual dosage of adjustment carbon equivalent (CE), greying coefficient (K) and alloying element C, Si, Mn, P, Cr, Mo, Cu, B, Sb, Ti;

The control of continuous casting drawing process parameter:

Section quality check continuously:

Section bar at X-ray inspection X

Section bar surface crack and the degree of depth＜0.5mm thereof can repair use;

Section bar surface cold shut, scab and the shrinkage cavity degree of depth＜1mm, can repair use;

All surface imperfection surpass above-mentioned size, scrap at once.

The later stage check of section bar:

The chemical ingredients check

Carbon, silicon, sulphur B quantitative elementary analysis, other alloying element spectroscopic analysis;

Metallographic examination

According to customer requirements, can check following conventional project at the different positions of section bar,

A. (do not corrode, 200X), be generally D type graphite, allow a small amount of E type to exist, graphite length of a film size is between 0.2～3.0mm for graphite form and size thereof;

B. carbide, iron phosphide eutectic form distribute and quantity, (4% nitric acid alcohol deep-etching, 200X);

C. ferrite and perlite quantity % (corrosion, 200X, 400X);

Mechanical performance test

A) tensile strength (σ b)

B) hardness (H _B)

Claims (4)

1. a boron phosphor alloy continuous casting section bar for iron casting is made up of C, Si, Mn, Cr, Mo, Cu, B, P, S, Sb, Ti, Fe; Its weight (%) is than being C:3.00-3.6, Si:1.80-2.90, Mn:0.40-0.80, Cr :≤0.20, Mo:0.10-0.50, Cu:0.40-1.00, B:0.02-0.15, P:0.30-0.80, S :≤0.06, Sb:0.02-0.15, Ti:0.08-0.15, Fe: surplus.

2. boron phosphor alloy continuous casting section bar for iron casting according to claim 1, its weight (%) be than being C:3.20-3.6, Si:1.80-2.30, Mn:0.60-0.80, Cr:0.15-0.20, Mo:0.30-0.50, Cu:0.80-1.00, B:0.08-0.12, P:0.50-0.80, S :≤0.06, Sb:0.04-0.06, Ti:0.10-0.15, Fe: surplus.

3. boron phosphor alloy continuous casting section bar for iron casting according to claim 1, its weight (%) be than being C:3.30-3.6, Si:2.50-2.90, Mn:0.40-0.60, Cr:0.07-0.12, Mo:0.15-0.30, Cu:0.40-0.60, B:0.04-0.06, P:0.30-0.50, S :≤0.06, Sb:0.02-0.03, Ti:0.08-0.12, Fe: surplus.

4. manufacture method as claimed in claim 1, realize by following steps:

Melting: adopt induction furnace or cupola furnace---the melting mode of induction furnace; Melting technology comprises:

Base iron, stokehold Rapid Thermal analyser controlled contents: carbon 3.20-3.60% and silicon 2.20-2.90%;

The alloy hot metal smelting temperature is 1460～1500 ° Celsius;

The method that pours in the hot metal ladle breeds, and 1400～1420 ° Celsius of pregnant preceding molten iron temperature breeds 7～9 minutes time length, breeds dosage 0.4～0.8%, nucleating agent granularity＜12mm.

Section bar spectroscopic analysis: determine Cr, Mo, Cu, Ti, Mn, S, P, Sb content;

The continuous casting drawing;

Mold structure;

The adjustment of temperature of cooling water, flow, pressure;

The adjustment of crystallizer outlet section bar surface temperature;

The adjustment of section bar pulling speed.