The Deformation Process Of Straight Seam Steel Pipes And Billets In The Forming Machine Is Very Comp

The Deformation Process Of Straight Seam Steel Pipes And Billets In The Forming Machine Is Very Complex, Including Longitudinal Deformation, Transverse Deformation Of Straight Seam Steel Pipes, And Cross-sectional Deformation.

(1) Longitudinal Deformation Refers To The Deformation Of The Billet In The Direction Of The Rolling Line During The Process Of Changing From A Flat Plate Shape To A Cylindrical Shape. Longitudinal Deformation Is Uneven. In The Pre Forming Section, The Extension L 'of The Edge Portion Of The Strip Steel Is Greater Than The Extension L Of The Center Portion, Reaching The Precision Forming Frame Before The Closed Hole Type, And The Extension L Of The Center Portion Is Greater Than The Extension L' Of The Edge Portion. This Longitudinal Uneven Deformation Is The Main Characteristic Of Strip Deformation In The Roll Continuous Forming Process.

Longitudinal Deformation Of Straight Seam Steel Pipe Strip

(2) Lateral Deformation Refers To The Cross-sectional Bending Deformation Of The Tube Blank In Each Forming Frame, That Is, The Deformation Generated By The Forming Hole Pattern. The Problem Of Transverse Bending Deformation Of The Tube Blank In Each Specific Hole Type Frame Is A Problem Of Roll Hole Design.

(3) Sectional Deformation Refers To The Change In The Wall Thickness Of The Steel Pipe Compared To The Thickness Of The Slab After Forming (including Actually Straightening And Sizing). The Change In Cross-sectional Wall Thickness Is Not Very Significant When Forming Thicker Walled Steel Pipes. When Forming Thin-walled Pipes, The Thickness Of The Straight Seam Steel Pipe Wall Slightly Increases Compared To The Thickness Of The Slab, And The Thickness Of The Pipe Wall On The Same Section Shows A Regular And Uneven Distribution. The Wall Thickness Of The Edge Part Is Smaller Than That Of The Bottom Part Of The Pipe, Which Is Due To The Extension Of The Edge. Due To The Small Deformation Of The Cross-section, It Has No Significant Impact On The Quality And Can Be Ignored. Generally, No Key Research Is Conducted.

Formed Tube Blank - Compared To Flat Strip Steel, Bending Deformation Only Occurs In A Plane Perpendicular To The Centerline Of The Strip Steel And The Tube: When The Strip Steel Is Formed Into A Tube, The Elongated Edge Of The Strip Steel Should Also Be Restored To The Same Length As The Middle Of The Strip Steel. This Involves Two Issues: Edge Extension And Rebound.

The Deformation Of The Strip Steel During The Actual Forming Of The Straight Seam Steel Pipe (4) Edge Extension And Rebound Is Much More Complex Than The Above Situation. In The General Rolling Continuous Forming Process, The Strip Steel Is Actually Formed In Sections, Which Is Called Step Forming. During The Step Forming Process, A Waveform Will Be Generated At The Edge Of The Strip Steel, As Shown In Figure 56. This Situation Will Inevitably Cause An Increase In Local Stress On The Strip Steel.

Further Research On The Deformation Of Strip Steel Between Any Two Adjacent Frames Can Be Divided Into Four Stages (see Figure 57): The Contact Section 1 Between The Strip Steel And The Forming Roller Surface; Contact Deformation Segment 2; Constant Shape Segment 3; Elastic Recovery Segment 4. The Edge Of The Strip Steel Is Stretched In The Non-contact Deformation Section, And This Tension Is Reduced In The Contact Section Between The Strip Steel And The Forming Roller Surface. There Is An Elastic Recovery Zone For A Section Of Strip Steel Behind The Forming Rack, Where The Elongated Strip Steel Fibers Have Obvious Shrinkage. There Is A Section Of Strip Steel Between The Elastic Recovery Section And The Non-contact Section That Does Not Deform. In This Section, The Deformation Process Of Straight Seam Steel Pipes And Billets Is Introduced When The Edge Of The Strip Steel Is Parallel To The Axis Of The Forming Machine.

Why Is Glass Lubricant Used In The Process Of Rolling Straight Seam Steel Pipes

The Die-casting Technology Of Metals Is No Longer A Secret. As Early As The 1930s, Western Countries Discovered That Steel, Like Other Softer Non-ferrous Metals, Can Be Deformed By Rolling. This New Process Quickly Spread As Soon As It Was Launched, Because Its Technology Is Simple And Easy To Learn, Production Equipment And Basic Costs Are Low, And The Products Produced Are Diverse And Reliable In Quality, With A Wide Range Of Uses. Therefore, The Improvement And Upgrading Of The Process Have Received Increasing Attention From Researchers. About Ten Years Later, A British Company Successfully Developed A Glass Lubricant, Which Rapidly Popularized The Process Of Rolling Straight Seam Steel Pipes In Countries Around The World.

Prior To This, The Traditional Steel Pipe Rolling Production Process Used Graphite As A Lubricant. However, Graphite Lubricants Have Their Fatal Drawbacks:

1. High Heat Transfer Efficiency, Poor Insulation, Fast Mold Heating, Fast Wear, And Difficulty In Rolling Long Products.

2. The Carbon Content Of The Product Is Relatively High, And Intergranular Corrosion Is Prone To Occur When Producing Stainless Steel. Therefore, The Carburized Layer Needs To Be Removed After Completion, Which Increases The Cost.

3. Increased Ecological Pollution And Damage.

Compared With Graphite Lubricants, Glass Lubricants Have The Following Advantages:

1. The Heat Transfer Efficiency Of Glass Is Low, And The Insulation Work On The Surface Of The Workpiece Is Done Well, Ensuring The Service Life Of The Mold.

2. The Lubrication Ability Is Three Times Higher Than Graphite, And The Production Rate And Width Are Correspondingly Increased, Which Can Expand The Product Range Produced By The Rolling Machine.

3. Glass Lubricants Have More Stable Chemical Properties And Will Not Cause Tissue Defects.

4. The Concentration Of Glass Can Be Adjusted Freely To Obtain Different Physical Properties (such As Softening Point, Viscosity, Etc.) To Meet The Needs Of Products Made Of Different Materials.

5. Clean And Environmentally Friendly, With No Toxic Side Effects And Minimal Environmental Damage. In Summary, Glass Lubricant Products Have Outstanding Performance. It Is An Essential Lubricant For The Production Of Straight Seam Steel Pipes.

The Three Areas That Must Be Well Lubricated When Producing Steel Pipes Are:

1. Rolling Mold: The Usual Lubrication Method For Rolling Molds Is To Press Glass Powder Into A Glass Pad. Before Starting To Roll Steel Pipes, The Glass Pad Is Sandwiched Between The Steel And The Rolling Mold. In Order To Achieve The Best Softening Effect Of The Glass Pad Under The Friction In The Middle, The Shape Of The Glass Pad Made Matches The Shape Of The Entrance Cone Of The Rolling Mold And The End Of The Steel.

2. Rolled Cylinder And Core Rod: The Glass Agent Used For Lubrication Of Rolled Cylinder And Core Rod Is In Powder Form, With Small Particle Size And Higher Softening Degree. It Is Then Applied To The Inner Hole And Outer Surface Of The Steel. In Addition, Glass Cloth Can Also Be Wrapped Around The Surface Of The Steel And Glass Cloth Strips Can Be Wrapped Around The Core Rod.

3. Removal Of Glass Film On The Surface Of Steel Pipes: Due To The Use Of Glass Lubricant During Rolling, A Thin Layer Of Glass Film Will Remain On The Inner And Outer Surfaces Of The Rolled Steel Pipes, Which Is Hard And Brittle Like Ordinary Glass, Affecting The Products After Use, So It Must Be Removed. There Are Mechanical And Chemical Methods For Removal. Mechanical Methods Include Shot Blasting, Water Cooling, And Stretching Straightening. If Chemical Methods Are Used To Remove Glass Films, We All Know That The Chemical Properties Of Glass Are Quite Stable, So If Chemical Methods Are Used, Strong Acid Or Strong Alkali Liquids Must Be Used. However, The Harm Of Acid Washing Method Is Its High Corrosiveness To Various Steel Pipe Materials, Which May Cause Over Pickling On The Surface Of The Steel Pipe, Especially For Carbon Steel, Which Is More Corrosive. It Is Not Cost-effective Or Suitable To Use Pickling Alone. So Now, Most People Use The Acid-base Combined Elimination Method.