Stainless Steel Tubing and Piping Standards

Stainless steel is typically comprised of a basic iron-derived steel alloy and approximately 11 percent chromium. Additives, such as nickel, can be added to help enhance or manipulate chromium’s characteristics. Said to be “stainless” because it resists corrosion, stainless steel’s resistance to wear and oxidation increases with the amount of chromium present in the metal. Additionally, stainless steel is relatively low-maintenance and clean, and does not compromise the purity or integrity of metals that it encounters. This is pertinent information to those working in the deep drawing process.

Stainless Steel Grades for Tubing and Piping

Because of its desirable traits, stainless steel is often used in piping and tubing applications. Not all grades of stainless steel serve the same function, so it is important to become familiar with differences between grades before selecting stainless steel for a specific application. In piping applications, type 304 stainless steel is the most commonly used alloy because of its corrosion resistance and suitability for use in chemical applications. Type 304 stainless steel is also used in food and beverage applications and paper mills. Because this type of steel has a maximum carbon content of .08 percent, it is subject to carbide precipitation at certain temperatures, which can result in failure. Therefore, 304 should not be used in applications where temperatures fall between 800 and 1640 degrees Fahrenheit.

Another type of stainless steel, type 304L, has a lower maximum carbon content (.03 percent), and is therefore able to withstand higher temperatures and can be welded—a quality that allows pipes to be interconnected without threading. In tubing and piping applications where acids and salts are encountered, type 318 is well-equipped because it contains a small amount (2 to 3 percent) molybdenum. For tubes and pipes involved in plastic manufacturing, type 316 is the preferable type of stainless steel.

Pipe and Tubing Standards and Specifications

Austenitic stainless steel, as used for tubing and piping, is produced according to these standards:

• ASTM A249 / ASME SA249

This specification is the standard for welded austenitic stainless steel for high temperature applications, such as boiler, heat-exchanger, and condenser tubes. Typically, the tubes are produced with 1/8 inch inside diameters and up to 5 inch outside diameters. To manufacture this grade of steel (which can include types 304, 304L, and 316, as well as types 316L, 317, and 321), there are three procedural steps: automatic welding (without any filler metal), testing each tube (hydrostatic or non-destructive electric testing), and then testing each tube for reverse-bend and hardness.

• ASTM A269

This standard specification applies to seamless and welded austenitic stainless steel tubing for general applications, including those that require general corrosion resistance and low and high temperature usage,  and can include types 304, 304 L, 316L and 321.Tubes are usually ¼ inch in inside diameter and more than .020’ in nominal wall thickness. Mechanical procedures are the same as for ASTM A249.

• ASTM A270

As the specification for seamless and welded austenitic stainless steel sanitary tubing, applications include tubes designated for food and beverage industry use, as well as those with special finishes. Because the tolerances are tighter for this standard, tube to tube fitting is more closing aligned. Tubes are made with inside diameters up to 6 inches.

• ASTM A312/ ASME SA312

For high temperature and general carrion resistance this specification for seamless and straight-seam welded stainless steel pipe applies. Appropriate grades include 304, 304L 316, 316L, 317, and 321. The manufacturing process lends itself to high-production runs because of the basic nature of the techniques and design. As a result, ASTM A312 is not appropriate for use as sanitary tubing, and is subject to size limitations—industrial piping of nominal pipe size (NPS) should instead be used for pharmaceutical facilities or other sensitive large-scale applications.

Other specifications, such as ASTM A358 (which designates the standards for chromium-nickel alloy stainless steel pipe for high temperature service), address other sizes, diameters, and temperature ranges for stainless steel piping and tubing. The specifications discussed above only address several common specifications and are do not constitute an exhaustive list.

Knowledge Base: Clutches

A clutch is a mechanical device designed to regulate rotation in different shaft components in an engine. They function is based on a passive and active rotation method with two different clutch plates that engage or disengage shafts. Typically, one clutch plate is driven by a shaft while the other clutch plate drives the other shaft. These two plates operate separately, but can be engaged to sync movement between the two shafts. Clutches are available in various designs to ensure proper and adequate mechanism engagement, and are common components of vehicular engines as well as other gas-powered devices that operate with wheel-based motors.

How Clutches Work

The design of a basic vehicular clutch involves many interlocking friction disc sections to connect an engine to a transmission. The engine connects to a flywheel, which is attached to the clutch plate within the clutch housing. The entire clutch housing connects to the transmission. There is also a lever or release fork attached to the clutch plate, which disengages the clutch from one of the drive shafts.

A clutch is needed to regulate shaft engagement because of variable rotation needs during engine operation. For instance, a car features a constantly rotating engine that only ceases movement when the car is turned off. However, the car wheels need to spin at different speeds in traffic and while idling. Electric drills use clutches to prevent the drill bit from turning once a screw presents resistance, preventing the drill from stripping the head or overdriving the screw. Automotive cooling systems utilize clutches with radiator cooling fans in order to cool the motor without wasting extra power. When the temperature is below the desired threshold, the fan clutch disengages to allow the fan to run on ambient wind, but when the motor temperature rises, the clutch engages to further cool the motor.

These uses illustrate the basic function of a clutch: to engage or disengage an active component of a device to an inactive component. When the components are engaged, the active component drives the inactive component, and when they are disengaged, the inactive component does not operate.

The reason a clutch can engage and cause rotation is that it capitalizes on the inherent friction properties of different surfaces. The friction discs in a clutch clamp together and use the pressure and friction to lock the different rotating clutches together. Friction discs are made of various materials, with more durable and higher friction coefficient materials being used in motors and applications with more power and more torque. For instance, ceramic friction discs are used in trucks to handle the high forces involved. Friction discs can either function dry or wet. Dry friction discs utilize materials with higher friction coefficients, while wet friction discs are coated in a lubricant fluid. This lubricant prevents dangerous heating by cooling the friction interaction between plates.

Clutch Problems

The friction and pressure harnessed for proper clutch function can also lead to deterioration in clutch materials. When a clutch fails to catch, the two mated surfaces grind into one another, as opposed to locking, and this strips away the material. If grooves or latches are present on a clutch surface, they can be stripped away fully to the point that the clutch will no longer fully engage and rotation movement cannot transfer. This is similar to a screw being “overturned” by a screwdriver. As the screwdriver disengages from the screw head, the metal grinds against the head and strips away the grooves, preventing full engagement. The clutch can be ground to the point where it will no longer engage, too.

When grinding sounds are emitted from an application using a clutch, it can be a sign that proper engagement is not occurring and surfaces are stripping. Most clutches are guaranteed for a long life before stripping necessitates replacement—this guarantee will normally be provided at time of purchase.

deep drawing copper fittings

Pipe fitting involves fixing the manner in which pipes that carry liquid or gas fit together, or performing basic pipe installation. Because different substances can have drastically different effects on pipes, several different materials are used in pipe fitting to ensure that the pipes can withstand the wear and tear incurred by the material they carry. Materials such as plastic, copper, steel, and iron, as well as clay, lead and aluminum, are all common choices for pipe fitting, depending on the specific application. Pipe fitting plays an important role in industries such as manufacturing and plumbing, where the proper selection, joining, and repair of pipes are essential to other dependent processes. Each type of pipe tubing calls for a pipe fitting, and different fittings exist to accommodate variations in materials and applications.

Copper Tubing and Fittings

Two types of copper tubing are typically used: soft and rigid. Because copper is corrosion-resistant, it’s a common choice for hot and cold water supply applications. Although it can be pricey, soft copper is a relatively easy to work with metal, making it suitable for applications that require bent tubing or unusual configurations. Rigid copper can be made softer through annealing, as can soft copper that has hardened through the drawing process. There are several different kinds of fittings used with drawing deep copper tubing: flare, sweat, and compression fittings are suitable for soft copper tubing, while elbow fittings must be used with rigid copper.

• Flare Fittings
In order to use a flare connection, the end of the tubing must be reworked into a male fitting. To alter the end of the tubing, a flare tool is used to manipulate the metal into a bell-shape, which is then compressed into a male fitting using a flare nut. The flare nut is what connects the tube to the fitting, creating a tight, leak-resistant juncture. The procedure is a cold-working process, meaning the metal need not be heated, and works well on soft copper as well as soft steel.

• Sweat Fittings
Sweat fittings are easy to use—they simply slide onto the end of a piece of copper tubing. To ensure the fitting stays in place, it is then heat treated with a torch to metal the metal. When the metal sweat fitting cools it bonds to the tubing, creating a secure joint. The process is relatively quick and easy, and is preferred in applications where many tube connections must be made at one time.

• Compression Fittings
Compression fittings use soft rings that slide into place over metal tubing, and are then further pushed into place over the connecting fitting. Because the compression ring is soft, it conforms to the shape of the tubing and fitting, producing a seal. However, compression fittings often call for reworking and tightening and take longer to create than a sweat fitting.

• Elbow Fitting
With hard copper, elbow fittings must be used. Because hard copper cannot be reshaped in its rigid form, a pre-shaped connector must be used to connect it to a fitting. Elbow fittings, resembling the human elbow in form (with two entrances for tubing, each at a 90 degree angle to one another), enable rigid copper tubing to change directions because the tubing cannot be bent. However, rigid copper can be heated, melted, and re-worked into a desired shape without damaging the metal.

Metal Deep Drawing News

We All Could Use A Little Good News With all the doom and gloom published in various news outlets each day, it would be refreshing to read some good news about manufacturing and the economy in general. So here are a couple links I’ve found to some “cup-half-full” blogs that cull stories reporting positive news. (You know, the stuff that doesn’t seem to get much media attention.) Check out The Good News Economist and Positive Economic News. In addition to reading the stories they’ve collected, you can contribute positive articles that you’ve found surfing the Internet. Modern Machine Shop’s “30-Second Survey” — Speaking of positivity and contribution, are current business and economic conditions generating feelings of optimism, or not so much? Let us know by taking our brief, 30-Second Survey. The survey results will be included in next month’s MMS Extra newsletter (but your names will remain confidential). Click here to complete the survey. Featured Product The DUO Series from Makino is the first wire EDM to offer a DuoSpark generator AND a dual wire guide option. This means faster, more accurate machining that increases cutting speeds by up to 30% and reduces wire consumption by as much as 40%. See the DUO43 and DUO64 machines in action at www.makino.com/DUO. New On MMS Online Revamped Video Page The appetite for metalworking videos is increasing, so we’ve updated our Web site’s video home page to streamline navigation. Check it out. The main box offers a series of rotating videos that you can select. In addition, categories below that box feature videos specific to certain machining topics, including machining centers, composites machining, micromachining, HSM, cutting tools, turning and grinding. In addition to the repository of videos, the page also highlights the most recent inMotion on-demand webinars. MMS Video and Webinars View Videos and inMotion on-demand webinars. heading Industry Information An Easy Way To Boost Productivity In this column, I cite a study in which U.S. manufacturing managers believe they will lose out on nearly half of their potential productivity gains this year. Steve Paulding, a cutting tool specialist for the Industrial Distribution Group, responded to me with what he says is a simple, yet effective way for shops using CNC lathes or mills to cut cycle times by 10 percent and improve tool life: Turn the feed rate override to 110 percent. Mr. Paulding says many shops have benefitted from this advice. He believes 6 seconds can be cut from every 60 seconds of cycle time, and every 30 minutes of tool life can be extended to 31.5 minutes. Don’t stop there. Mr. Paulding suggests running with the override at 110 percent for a little while. If no part-quality or tool-life issues arise, edit the part program with the higher feed rate and drop the override back to 100 percent. If all continues to go well, bump up the override to 110 percent and see if you achieve more gains. By continuing this process until a problem arises, Mr. Paulding says you’ll know how far you can push your tools and machines. Read More. Section Break Your Thoughts Throwing Your Hat In The Wind Energy Ring? There are signs that the United States will soon start making the move to wind power in earnest. However, I suspect that the country lacks the big machining capacity needed to meet the potential demand for large turbine components such as rotor hubs. Do you have the capacity to machine such sizeable parts, and are you poising your shop to support the wind energy market? Or, has the potential for winning new business in this alternative energy segment spurred you to consider adding large machines? Please share your thoughts. If we publish your response, you’ll receive a copy of Modern Machine Shop’s Handbook for the Metalworking Industries. To respond, send an e-mail to Derek. Break Metalworking Mojo Can You Weld Aluminum Foil? Although we primarily focus on the chip-making operations shops perform, this welding “parlor trick” on Miller Electric’s Web site is worth a look-see. The trick—welding together two pieces of aluminum foil—is performed by Ron Covell, owner of Covell Creative Metalworking. Mr. Covell’s customized cars and motorcycles have been featured in a number of magazines. His Web site has examples of his handiwork and numerous welding instructional DVDs that he offers. Give this trick a shot! Welding View Video Break Our Next IssueJune Cover Caves, Knobs, Molds And Tubes The cover story for the June issue of Modern Machine Shop describes an instruments manufacturer—located in a man-made cave, no less—that found lean manufacturing could lead to accelerated product development. Another feature cautions that overlooking the unassuming retention knob can decrease tool life. We also explain why a moldmaking operation added an advanced six-axis gundrilling machine as part of its efforts to streamline every step of the mold-building process. Also, find out how a Texas shop addresses the challenges honing long oil rig components.

engineering calculations

SECTION 1
STRUCTURAL STEEL
ENGINEERING
AND DESIGN
MAX KURTZ, P.E.
Consulting Engineer
METRICATED BY
GERALD M. EISENBERG
Project Engineering Administrator
American Society of Mechanical Engineers
Part 1: Statics, Stress and Strain, and Flexural Analysis
PRINCIPLES OF STATICS; GEOMETRIC PROPERTIES OF AREAS
Graphical Analysis of a Force System
Analysis of Static Friction
Analysis of a Structural Frame
Graphical Analysis of a Plane Truss
Truss Analysis by the Method of Joints
Truss Analysis by the Method of Sections
Reactions of a Three-Hinged Arch
Length of Cable Carrying Known Loads
Parabolic Cable Tension and Length
Catenary Cable Sag and Distance between Supports
Stability of a Retaining Wall
Analysis of a Simple Space Truss
Analysis of a Compound Space Truss
Geometric Properties of an Area
Product of Inertia of an Area
Properties of an Area with Respect to Rotated Axes
ANALYSIS OF STRESS AND STRAIN
Stress Caused by an Axial Load
Deformation Caused by an Axial Load
Deformation of a Built-Up Member
Reactions at Elastic Supports
Analysis of Cable Supporting a Concentrated Load
Displacement of Truss Joint
Axial Stress Caused by Impact Load
Stresses on an Oblique Plane
Evaluation of Principal Stresses
Hoop Stress in Thin- Walled Cylinder under Pressure

1.87
Part 2: Structural Steel Design
STEEL BEAMS AND PLATE GIRDERS
Most Economic Section for a Beam with a Continuous Lateral Support
under a Uniform Load
Most Economic Section for a Beam with Intermittent Lateral Support
under Uniform Load
Design of a Beam with Reduced Allowable Stress
Design of a Cover-Plated Beam
Design of a Continuous Beam
Shearing Stress in a Beam — Exact Method
Shearing Stress in a Beam — Approximate Method
Moment Capacity of a Welded Plate Girder
Analysis of a Riveted Plate Girder
Design of a Welded Plate Girder
STEEL COLUMNS AND TENSION MEMBERS
Capacity of a Built-Up Column
Capacity of a Double- Angle Star Strut
Section Selection for a Column with Two Effective Lengths
Stress in Column with Partial Restraint against Rotation
Lacing of Built-Up Column
Selection of a Column with a Load at an Intermediate Level
Design of an Axial Member for Fatigue
Investigation of a Beam Column
Application of Beam-Column Factors
Net Section of a Tension Member
Design of a Double- Angle Tension Member
PLASTIC DESIGN OF STEEL STRUCTURES
Allowable Load on Bar Supported by Rods
Determination of Section Shape Factors
Determination of Ultimate Load by the Static Method
Determining the Ultimate Load by the Mechanism Method
Analysis of a Fixed-End Beam under Concentrated Load
Analysis of a Two-Span Beam with Concentrated Loads
Selection of Sizes for a Continuous Beam
Mechanism-Method Analysis of a Rectangular Portal Frame
Analysis of a Rectangular Portal Frame by the Static Method
Theorem of Composite Mechanisms
Analysis of an Unsymmetric Rectangular Portal Frame
Analysis of Gable Frame by Static Method
Theorem of Virtual Displacements
Gable-Frame Analysis by Using the Mechanism Method
Reduction in Plastic-Moment Capacity Caused by Axial Force
LOAD AND RESISTANCE FACTOR METHOD
Determining If a Given Beam Is Compact or Non-Compact
Determining Column Axial Shortening with a Specified Load
Determining the Compressive Strength of a Welded Section
Determining Beam Flexural Design Strength for Minor- and
Maj or- Axis Bending
Designing Web Stiffeners for Welded Beams
Determining the Design Moment and Shear Strength of a Built-up
Wide-Flanged Welded Beam Section
Finding the Lightest Section to Support a Specified Load
1.88

Combined Flexure and Compression in Beam-Columns in a Braced Frame
Selection of a Concrete-Filled Steel Column
Determining Design Compressive Strength of Composite Columns
Analyzing a Concrete Slab for Composite Action
Determining the Design Shear Strength of a Beam Web
Determining a Bearing Plate for a Beam and Its End Reaction
Determining Beam Length to Eliminate Bearing Plate
Part 3: Hangers and Connections, Wind-Shear Analysis
Design of an Eyebar
Analysis of a Steel Hanger
Analysis of a Gusset Plate
Design of a Semirigid Connection
Riveted Moment Connection
Design of a Welded Flexible Beam Connection
Design of a Welded Seated Beam Connection
Design of a Welded Moment Connection
Rectangular Knee of Rigid Bent
Curved Knee of Rigid Bent
Base Plate for Steel Column Carrying Axial Load
Base for Steel Column with End Moment
Grillage Support for Column
Wind-Stress Analysis by Portal Method
Wind-Stress Analysis by Cantilever Method
Wind-Stress Analysis by Slope-Deflection Method
Wind Drift of a Building
Reduction in Wind Drift by Using Diagonal Bracing
Light-Gage Steel Beam with Unstiffened Flange
Light-Gage Steel Beam with Stiffened Compression Flange

the deep drawing process

deep drawing process demo