### 1. What is the difference between ASTM and ASME pipe?
The key difference lies in the scope and purpose of the standards set by these two organizations.
* **ASTM (American Society for Testing and Materials)** is a materials specification society. An **ASTM** standard (e.g., A106, A53) defines the *chemical composition*, *mechanical properties* (like tensile strength and yield strength), *manufacturing process* (seamless or welded), and *testing methods* for the raw pipe material itself. It specifies what the pipe is made of and its basic properties.
* **ASME (American Society of Mechanical Engineers)** is a design and construction code society. An **ASME** standard (which often adopts ASTM material specs) defines the *allowable design stress*, *pressure-temperature ratings*, *fabrication methods*, and *inspection requirements* for that pipe when it is used in a specific application, such as a power plant or pressure vessel. It specifies how the pipe must be used in a system.
In short: **ASTM specifies the material and manufacture of the pipe. ASME specifies how to use that pipe in a pressurized system.** A pipe can meet an ASTM specification but not be acceptable for an ASME code application if it hasn't been produced and certified to the additional ASME requirements.
---
### 2. What is ASTM A106 and ASME SA106?
This is a perfect example of the relationship between ASTM and ASME.
* **ASTM A106** is the standard specification for seamless carbon steel pipe designed for high-temperature service. It covers the chemical, mechanical, and dimensional requirements for the pipe.
* **ASME SA106** is the ASME Boiler and Pressure Vessel Code (BPVC) designation that *fully adopts* the ASTM A106 specification. When a pipe manufacturer produces a pipe to the A106 standard and follows additional quality assurance and certification procedures required by the ASME code, they can stamp it as **SA106**.
Essentially, the material is the same. The "S" in SA106 signifies it is an ASME code material suitable for use in boilers, pressure vessels, and other high-pressure systems governed by ASME rules.
---
### 3. What is the ASTM standard for steel?
ASTM does not have a single standard for steel. Instead, it has hundreds of different standards that cover the vast range of steel types, grades, and intended uses. These standards are organized by the type of steel:
* **Carbon Steel:** Standards like A53 (general use), A106 (high-temperature service), A500 (structural tubing).
* **Alloy Steel:** Standards like A335 (seamless ferritic alloy-steel pipe for high temperature).
* **Stainless Steel:** Standards like A312 (seamless and welded stainless steel pipe).
* **Structural Steel:** Standards like A36 (carbon structural steel) and A500 (structural tubing).
Each standard defines the specific requirements for the steel it covers.
---
### 4. What is the ASTM standard for Schedule 40 steel pipe?
"Schedule 40" is not an ASTM standard itself; it is a **wall thickness designation** defined by ASME B36.10M (for carbon and alloy steel) and ASME B36.19M (for stainless steel). It indicates a specific thickness for a given pipe diameter.
Several ASTM pipe standards include pipes that are made in Schedule 40 thickness. The most common ones are:
* **ASTM A53:** Grade B (Seamless or Welded) - for general purpose and low-pressure transport.
* **ASTM A106:** Grade B - for high-temperature service.
* **ASTM A500:** Grade B or C - for structural applications.
* **ASTM A312:** Type 304/304L - for stainless steel corrosion-resistant applications.
So, you would specify a pipe as **"ASTM A53 Grade B, Schedule 40"** or **"ASTM A106 Grade B, Schedule 40."**
---
### 5. Is the ASTM A53 schedule 40?
**ASTM A53 is not itself Schedule 40.** ASTM A53 is a material standard that defines the chemical and mechanical properties of the pipe.
However, pipe that conforms to the **ASTM A53 standard is very commonly manufactured and available in Schedule 40 wall thickness**, among others (like Schedule 80, 160, STD, XS). So, it is correct to order or refer to a pipe as **"ASTM A53 Schedule 40."** This means the pipe meets the material requirements of A53 and the dimensional wall thickness requirements of Schedule 40.
