ASTM A500

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Stratusteel
Next Generation HSS

We’re taking high-strength, lightweight steel to new heights.

BMT Welding Guide for Stratusteel used in transportation and other heavy equipment industries. In this guide you will find suggestions for using Stratusteel tubing in applications such as transportation and heavy equipment. This is intended to be a general guideline only—please always refer to your tube manufacturer or raw steel provider’s specifications where necessary.

Table of Contents

Introduction 3

1. Preparation 4
2. Welding 4
3. Recommended Welding Materials for Stratusteel  4

Table #1: Recommended weld wire for Stratusteel 4

4. Preheat and Inter-pass Temperature Considerations 5
5. Hydrogen Cracking Risks 5

Table #2: Rules of thumb for handling prior to welding 5

6. Heat Affected Zone (HAZ) or Soft Zones 5
7. Direction and Passes for Welding 6

Figure #1: Impact of starting welds in joint locations 6

Figure #2: Improved impact of starting welds in parent material 6

7.1. Welding Parameters Analyzed  7

Table #3: Weld parameters used for thermal stress analysis  7

7.2 Real-World Example of Welding Parameters Used in Construction of Trailer Frames  7

Table #4: Weld Parameters used during real-world construction of 8-gauge 3”x5” Stratusteel 7

8. Fabrication Considerations 8
9. Final Considerations 8

Stratusteel™ hollow steel tubing from Bull Moose is stronger than steel, and lighter than aluminum configured to bear the same load. As a result, you can reduce the weight of your design by as much as 35% while getting the strength and other benefits  of steel. With Stratusteel, your designs will be dramatically lighter, stronger, and more efficient!

Introduction 

Welding  of Stratusteel will be different than typical A500 50MY – 80MY tubing. Stratusteel is greater  than or equal to 100MY, and as a result, welding requirements are slightly different. When  welded  properly, Stratusteel will ensure long-lasting performance  while making your designs lighter, stronger  and more efficient to manufacture.

1. Preparation 

All well-established methods or processes of preparation can be used with Stratusteel.   However, attention should be paid to any potential buildup of materials on the surface of weld joint, such as thin oxides films from thermal cutting. Make sure all joints are well cleaned prior to welding.  If using a plasma cutting for joint preparation, oxygen should be used to minimize risk of porosity in the weld material during welding. It is also possible to use a grinding method, which would remove the risk of porosity in the weld material. It’s recommended to grind down by at least 0.2mm if using this method post plasma cutting. 

2. Welding  

All common fusion welding methods can be used for welding Stratusteel, such as: 

• MAG/MIG – Welding 
• MMA-Welding 
• TIG-Welding 
• Plasma Welding 
• Submerged Arc Welding 
• Laser Welding 

While other methods can be used, these are the most common for Stratusteel. Of these, MAG/MIG welding is the most commonly used welding technique known today. When T-joint welds are close to the edge with a thickness ≥ 8 mm, there should be no sharp defects at the edge. Such defects can lead to stresses in the thickness direction, which can lead to cracking during welding. These welds should be avoided. Shearing is not expected in the use of Stratusteel due to its shape and size. However, if shearing is used, welding should not occur near the sheared area, as it gives increases in stress at the shear location (which can lead to cracking at the weld location in contact with the shear location). It’s recommended that if the location must be used, that it’s  thermally cut instead of sheared. 

3. Recommended Welding Materials for Stratusteel

Stratusteel should be welded with high strength solid welding wire

Table #1: Recommended weld wire for Stratusteel

4. Preheat and Inter-pass Temperature Considerations 

Multi-pass welding may cause the temperature in the welded joint to rise to a level that causes the strength to drop. This is most critical for welds below 500mm, because the temperature will drop between weld bead formations.  The maximum inter-pass temperature for Stratusteel is  100 degrees C.  For short welds, it is recommended to allow the temperature to cool to 150  degrees C prior to starting the next weld bead. For best results, it is recommended for Stratusteel to be at standard room temperature (temp ≥  23 degrees C ≤100 degrees C) prior to welding. 

5. Hydrogen Cracking Risks 

This risk of hydrogen cracking is very low; however, it can occur under very specific conditions. Hydrogen cracking will occur if European Standard 1011-2 is met, whereby a very high hydrogen content > 15 ml/100g of weld metal material and an extremely low heat input of < 0.5Kj/mm are applied, with a combined thickness of 30mm of Stratusteel.  These conditions are very rare— however, it is critical to monitor and prevent these conditions in order avoid risk of hydrogen cracking during welding.  To avoid this risk, it’s recommend that you use weld materials with low hydrogen content ≤ 10 ml/100g weld metal. When welding Stratusteel it’s important to also follow good general welding practice to avoid increased risk of hydrogen cracking. Rules of thumb to follow to minimize hydrogen cracking are:

Table #2: Rules of thumb for handling prior to welding

6. Heat Affected Zone (HAZ) or Soft Zones When using Stratusteel, soft zones can form in the HAZ.  This can happen as a result of changes in the microstructure during welding.  However, if normal heat inputs are used, then these soft zones typically do not influence the strength of the weld.  For example, if an inter-pass temperature of 150 degrees C is maintained using a single pass, then the heat input which would affect Stratusteel could be increased by 10 – 15% for a butt weld, and approximately 40 – 50% for a filet weld. Following the inter-pass temperature limits will reduce if not eliminate any impact in HAZ leading to soft zones.

7. Direction and Passes for Welding When using Stratusteel we recommend that you start your weld bead in the larger section of the parent material and then work towards the joint. For two pass welds we recommend that once at the joint, the welder restart from the larger section going into the joint (as opposed to returning from the joint to larger section).  Please see figure #1 as a representation of starting welds at joint locations.

Restarting second pass welds in the larger parent material allows for inter pass cooling and reduction of stresses at the joint.  If welding a plate, it is recommended that the plate use a  notch of at least 1” in radius at the joint to prevent concentration of stresses at the joint an follow the inter pass recommendations above.

7.1. Welding Parameters Analyzed As part of this guide, extensive thermal analysis was performed in order to generate stress analysis curves and impact of welding conditions.  Below is the table of welding parameters used  for this section: 

Table #3: Weld parameters used for thermal stress analysis

7.2 Real-World Example of Welding Parameters Used in Construction of Trailer Frames Below is a table of real-world welding parameters which yielded the best results for the gauge of  tubing applied:

Table #4: Weld Parameters used during real-world construction of 8-gauge 3”x5” Stratusteel

8.    Fabrication Considerations When fabricating (welding) Stratusteel HSS, consideration should be taken to reduce the residual stresses imparted into the HSS from the shop/field welding process. The weld seam on the HSS should be oriented, if possible, where thermal stresses will not affect the weld seam. For example, orienting the HSS weld seam in a restrained position under a reinforcement plate, bracket, etc., to minimize buildup of residual stresses. Cutouts and holes, where possible,  should be placed away from or opposite the weld seam face.

9.    Final Considerations All steps mentioned above should be taken when welding Stratusteel.  In addition, you should make every effort to have a clean, moisture-free weld area for best results.  Condensation, dirt,  and any other foreign material should be removed prior to welding.  Always monitor and prevent conditions that could cause hydrogen cracking. Please feel free to contact us at Bull Moose Tube Technical Support with any questions or concerns. Bull Moose maintains an unwavering commitment to quality, precision, and technical expertise. For reliable technical support, or capable collaboration with product development, please call  888.227.5430, or email techsupport@bullmoosetube.com.

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Depend on the strength and reliability of Bull Moose when it comes to hollow Structural Steel Tube.

Our products stand the test of time. Whether exposed to the elements or hidden behind walls, we know that your structure and tenants are counting on us. You need reliable service and products of exceptional strength. You need Bull Moose.

Direct-form manufacturing makes us unique. Direct-form means we can use the highest grade HSLA steel, which is directly formed into a tube. This minimizes the cold-working process, which can change the characteristics of the steel.

BULL MOOSE ADVANTAGES: 

• Tubes with strength ranges of 46 KSI to 110 KSI 
• Tighter tolerances, sharper edges and straighter tubes 
• Widest variety of custom sizes and lengths, including metric sizes and cut-to- length options

OTHER BENEFITS/SERVICES:

• Specialized packaging
• Leading availability and fastest delivery due through 8 North American sites
• Readily available weathering grade steel
• Readily available Charpy V-Notch steel
• In-line NDT weld testing available on all tube

Leading the Herd

Founded in 1962, Bull Moose Tube has been delivering products of formidable quality for more than half a century. With sizes ranging from 1-1/2” square through 18” x 6” rectangle, and wall thicknesses of 1/8” through 5/8” Bull Moose features one of the largest size ranges of HSS products in the industry.

And with eight North American manufacturing and warehouse facilities, Bull Moose has the HSS products you need when you need them.

You need strength and reliability. You need availability.

You need Bull Moose Tube.

EIGHT WORLD-CLASS LOCATIONS DELIVERING BEST-IN-CLASS PRODUCTS

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Stratusteel

110 KSI Steel Tube

It’s Might… Made Light™.

The Strongest, Lightest Steel Tubes on the Planet

LIGHTWEIGHT STEEL WITH HEAVYWEIGHT PERFORMANCE

Stratusteel®  is a revolutionary hollow structural steel tubing that delivers an extraordinary set of characteristics:

High Strength = Yield strengths as high as 110KSI, enabling your products to support greater loads and span greater distances.

Light Weight = 35% lighter than an equivalent A500 50KSI product!

2x Harder than Steel = Your products become more durable and sustainable; remain better-looking, longer.

CUSTOM SIZES AND PROFILES

Stratusteel is available in a broad range of standard and metric sizes. But our variable tooling mills also allow for custom tube profiles. We can optimize wall thickness and outer dimensions/contours for your specific needs.

Customizing for your exact application saves you from buying bulkier stock than you really need…making Stratusteel a high value custom product for a standard steel price!

Here’s an example:

Your design shows that a 3.83” x 5.75” x 0.197” HSS will work on your product (weighing 11.98 lbs/ft.).

If the nearest size in conventional HSS is 4” x 6” x .025” (weighing 15.62 lbs/ft.), you’ll experience an unnecessary 23% increase in weight and thus a 23% increase in cost!

Stratusteel would enable you to avoid those increases with efficient, optimal dimensions and weight.

HOW DOES STRATUSTEEL BENEFIT YOU? 

ENGINEERS: Explore new design options with lighter, more streamlined products. Switching to Stratusteel

from ASTM A500 Grade B can enable a wall thickness reduction of 35%. It may even enable you to reduce the number of steel components in your assembled product.

PURCHASING AGENTS: Every pound of steel you don’t have to buy is a direct savings for your bottom line.

SHIPPERS: Smaller, lighter products mean fuller shipments and lower shipping costs. This enables you to

get the most out of every freight mile—ultimately reduces demands on drivers’ time, and fuel consumption.

MARKETERS: With Stratusteel, your product may potentially be positioned as the lightest, strongest of its kind on the market.

Finishes available:

• Post-pickled in oil
• EPS (Eco-Pickled Surface)

Stratusteel

Contact us to explore the advantages Stratusteel can bring your product line!

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HSS STRATUSTEEL®–100 SECTION PROPERTIES / SQUARES & RECTANGLES

HSS STRATUSTEEL®–100 SECTION PROPERTIES / SQUARES & RECTANGLES

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A500 / SQUARES

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This publication presents tables of dimensions and section properties for rectangular Hollow Structural Sections (HSS) produced by Bull Moose Tube Company.

The dimensions, including nominal width, nominal depth, nominal diameter and nominal wall thickness are subject to the permissible variations stipulated in ASTM A500 “Standard Specification for Cold-Formed Welded and Seamless Carbon Steel Structural Tubing in Rounds and Shapes.”

With today’s manufacturing methods, HSS are produced to more precision than in the past. The strip used to produce HSS is now ordered to thicknesses with tighter tolerances. As a result, ERW HSS manufactured to ASTM A500 will often have a wall thickness close to the Specification allowable value.

In a change from past practice, section property data is now based upon the design wall thickness. The design wall thickness, t, for ERW HSS is less than the specified nominal wall thickness. The design wall

thickness for each HSS size is included in the tabulated data.

The section property data based upon the design wall thickness, t, results in variations in the published area data that do not exceed 3.50% of the data based upon the minimum permissible wall thickness stipulated in ASTM A500. This is consistent with the similar section property data published for hot rolled structural shapes and the manufacturing tolerances associated with those products. The section property data for rectangular ERW HSS are based upon outside corner radii equal to 2.0 times the design wall thickness.

These tables contain all HSS sizes produced by Bull Moose Tube Company as well as current capability to produce sizes. Check with our sales department for current availability.

The more universal terms “Hollow Structural Section” and “HSS” are used in this publication to designate rectangular structural steel tubing. These terms replace “structural tubing” and “pipe,” which had

been used previously.

The information presented in this publication has been prepared in accordance with recognized engineering principles and is for general information only. While it is believed to be accurate, this information should not be used or relied upon for any specific application without competent professional examination and verification of its accuracy, suitability, and applicability by a licensed professional engineer, designer, or architect. The publication of the material contained herein is not intended as a representation or warranty on the part of Bull Moose Tube Company, that this information is suitable for any general or particular use or of freedom from infringement of any patent or patents. Anyone making use of this information assumes all liability arising from such use.

Caution must be exercised when relying upon other specifications and codes developed by other bodies and incorporated by reference herein since such material may be modified or amended from time

to time subsequent to the publishing of this edition. Bull Moose Tube Company bears no responsibility for such material other than to refer to it and incorporate it by reference at the time of the initial publication of this edition.

HSS SECTION PROPERTIES / RECTANGLES

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Document Text:

This publication presents tables of dimensions and section properties for square Hollow Structural Sections (HSS) produced by Bull Moose Tube Company.

The dimensions, including nominal width, nominal depth, nominal diameter and nominal wall thickness are subject to the permissible variations stipulated in ASTM A500 “Standard Specification for Cold-Formed Welded and Seamless Carbon Steel Structural Tubing in Rounds and Shapes.”

With today’s manufacturing methods, HSS are produced to more precision than in the past. The strip used to produce HSS is now ordered to thicknesses with tighter tolerances. As a result, ERW HSS manufactured to ASTM A500 will often have a wall thickness close to the Specification allowable value.

In a change from past practice, section property data is now based upon the design wall thickness. The design wall thickness, t, for ERW HSS is less than the specified nominal wall thickness. The design wall

thickness for each HSS size is included in the tabulated data.

The section property data based upon the design wall thickness, t, results in variations in the published area data that do not exceed 3.50% of the data based upon the minimum permissible wall thickness stipulated in ASTM A500. This is consistent with the similar section property data published for hot rolled structural shapes and the manufacturing tolerances associated with those products. The section property data for square ERW HSS are based upon outside corner radii equal to 2.0 times the design wall thickness.

These tables contain all HSS sizes produced by Bull Moose Tube Company as well as current capability to produce sizes. Check with our sales department for current availability. The more universal terms “Hollow Structural Section” and “HSS” are used in this publication to designate square structural steel tubing.

These terms replace “structural tubing” and “pipe,” which had been used previously.

The information presented in this publication has been prepared in accordance with recognized engineering principles and is for general information only. While it is believed to be accurate, this information should not be used or relied upon for any specific application without competent professional examination and verification of its accuracy, suitability, and applicability by a licensed professional engineer, designer, or architect. The publication of the material contained herein is not intended as a representation or warranty on the part of Bull Moose Tube Company, that this information is suitable for any general or particular use or of freedom from infringement of any patent or patents. Anyone making use of this information assumes all liability arising from such use.

Caution must be exercised when relying upon other specifications and codes developed by other bodies and incorporated by reference herein since such material may be modified or amended from time

to time subsequent to the publishing of this edition. Bull Moose Tube Company bears no responsibility for such material other than to refer to it and incorporate it by reference at the time of the initial publication of this edition.

HSS SECTION PROPERTIES / SQUARES

HSS SECTION PROPERTIES / SQUARES

HSS SECTION PROPERTIES / SQUARES